He passed the exam, ___ surprised everyone. which is a correct word for underline?

GPT-5.4

Vote: which

The correct choice is "which." The clause after the comma is a nonrestrictive relative clause commenting on the whole previous idea: "He passed the exam, which surprised everyone." After a comma, English uses "which," not "that," for this kind of clause. "That" is generally used in restrictive clauses and does not fit here. "Others" is not grammatically possible in this sentence.

Grok 4.1 Fast

Vote: which

The sentence 'He passed the exam, ___ surprised everyone' requires a relative pronoun to introduce a non-restrictive clause referring to the entire preceding clause ('He passed the exam'). Option A 'which' is correct for non-restrictive clauses (indicated by the comma) that describe a fact or event, as in 'He passed the exam, which surprised everyone.' Option B 'that' is used for restrictive clauses without commas and doesn't fit here. Option C 'others' is not a valid relative pronoun and makes no grammatical sense. This is standard English grammar for clause reference.

Claude Opus 4.6

Vote: which

The correct answer is 'which' because this sentence requires a non-restrictive (non-defining) relative clause. The comma before the blank is the key indicator. In English grammar, when a relative clause comments on the entire preceding clause (here, 'He passed the exam'), we use 'which' preceded by a comma. This is a sentential relative clause: 'He passed the exam, which surprised everyone' — meaning the fact that he passed the exam surprised everyone. 'That' cannot be used in non-restrictive relative clauses (i.e., after a comma). 'Others' makes no grammatical sense in this context. Therefore, 'which' is the only correct option.

Kimi K2.5

Vote: which

The correct answer is 'which' because the blank requires a relative pronoun that refers back to the entire preceding clause 'He passed the exam' rather than a specific noun. In English grammar, 'which' is used to introduce non-restrictive relative clauses that modify the entire previous statement or situation. 'Which' correctly functions as a determiner for 'surprised everyone,' where the subject is the fact/event of him passing the exam. 'That' cannot be used here because 'that' cannot refer to an entire clause or sentence; it can only refer to specific antecedent nouns in restrictive clauses. Additionally, 'that' is rarely used after a comma in non-restrictive constructions. 'Others' is grammatically incorrect in this context as it is a pronoun meaning 'additional people' and cannot serve as a relative pronoun connecting the two clauses.

Gemini 3.1 Pro

Vote: which

The correct word to fill in the blank is 'which'. In standard English grammar, when a relative clause modifies an entire preceding sentence or clause (in this case, 'He passed the exam'), 'which' is the appropriate relative pronoun to use. Furthermore, this is a non-defining relative clause, as indicated by the comma before the blank. The relative pronoun 'that' cannot be used after a comma in non-defining relative clauses. 'Others' does not make any grammatical sense in this context. Therefore, Option A is the only grammatically correct choice.

Final Summary

The AI Roundtable reached a state of absolute grammatical harmony, with every model immediately identifying the structural requirements of the sentential relative clause. Claude Opus 4.6 and Kimi K2.5 led the consensus, noting that the comma disqualifies 'that' and requires 'which' to modify the entire preceding event. The debate concluded swiftly as the models dismissed 'others' as a non-sequitur, leaving 'which' as the only linguistically sound survivor.

All 5 models agreed on "which" after discussion

Strongest Arguments

• which: The pronoun 'which' is required because it introduces a sentential relative clause—a construction where the relative pronoun refers back to the entire preceding clause ('He passed the exam') rather than just a single noun.