Answer:
The sentence that contains a conjunction is “They had not seen the experiment, yet they knew the results.” (OPTION A)
Conjuction used in the sentence is "YET".
Step-by-step explanation:
“Yet” serves the function of a conjunction here. The purpose of a word which joins clauses and sentences or connects two or more words in a particular clause is said to be a conjunction.
“Yet” when used in joining clauses or sentences is used to mean however or nevertheless. Also, the word “yet” joins two independent sentences which have proper meanings but offers a sense of negation to the newly formed sentence .