[1] Tia and Jackie are partners in science class. [2] They have a big project to complete and are having trouble agreeing on an idea. [3] Jackie would prefer to study geology, but Tia is more interested in human biology. [4] Ultimately, they decides to study fossilization.
Which sentence has a subject-verb agreement error?
A) [1]
B) [2]
C) [3]
D) [4]