Explanation
Correct answer: B.
Choice B is the best answer. The convention being tested is the use of verb forms within a sentence. The nonfinite present participle “searching” is correctly used to form a supplementary element that modifies the subject “scientists,” indicating that the scientists who adapted the test were looking for evidence of self-awareness in snakes.
Why the other choices are wrong
Choice A
Choice A is incorrect because it results in an ungrammatical sentence. The finite past tense verb “searched” can’t be used in this way to form a supplementary element that indicates what evidence the scientists who adapted the test were looking for.
Choice C
Choice C is incorrect because it results in an ungrammatical sentence. The finite past progressive verb “were searching” can’t be used in this way to form a supplementary element that indicates what evidence the scientists who adapted the test were looking for.
Choice D
Choice D is incorrect because it results in an ungrammatical sentence. The finite present perfect verb “have searched” can’t be used in this way to form a supplementary element that indicates what evidence the scientists who adapted the test were looking for.
Student discussion
marcosat 1 likes
any other answer results in a complete sentece. As a result, it breakes the structure of the passage as there are two independent sentences concatenated by a comma. As there isn't a FANBOYS, the prior sentence must be a dependent one.