Question

In which sentence is the correct pronoun used? If June studies architecture, her can design buildings. If June studies architecture, she can design buildings. If June studies architecture, you can design buildings.

Answer 1

The answer is  If June studies architecture, she can design buildings.

Answer 2

The correct answer is "If June studies architecture, she can design buildings." 
The other three are not grammatically correct, and do not make much sense when reading them aloud.