Concept:The pattern “so ... that” is used to show a result caused by a high degree of a quality.Explanation:The sentence needs a word that connects “simple” with the result that follows.The correct structure is “so + adjective + that.”Here, “simple” is the adjective, and “that we thought we would all pass” gives the result.So the sentence becomes: “The test seemed so simple that we thought we would all pass.”Option B is therefore the correct choice.Answer:so