Art can reflect the ideas and feelings of the artist in a way that viewers can

a. Believe

b. Relate to

c. Understand

d. Imagine

Understand is the answer

Art can reflect the ideas and feelings of the artist in a way that viewers can C. understand.

I don't think A is correct because you don't necessarily have to believe in what you see in front of you when it comes to art. You don't have to believe in what the artist is trying to show you. The same thing goes for B. When it comes to D, there isn't much to imagine if you see it there, which means I'd go with C.