We should notice quickly that some answer choices use "who", while others use "whom". "Who" and "whom" are not interchangeable, so we know we should be able to eliminate either 2 or 3 answer choices. A good trick: we should be able to replace/answer "who" with "he/she/they" and "whom" with "him/her/them" - this is because "who" refers to subjects, while "whom" refers to objects.

Trying this with our sentence, we recognize that we would say "Picasso met him", not "Picasso met he". So we want to use "whom" in our sentence and can eliminate A and E.

Looking between B, C, and D, we see that only our list of things that appear in Rose Period images located at the end of the sentence changes. When we have a list, we should first look to see if all things in the list are parallel. If not, we can eliminate:

B. images of:
- harlequins
- acrobatic
- other circus people
Here, our first and third list item are nouns, while our second list item is an adjective. Not parallel - eliminate.

C. images of:
- acrobats
- harlequins
- other circus people
All three list items are nouns! Parallel - keep this one.

D. images of:
- acrobats
- harlequins
- shows other circus people
The third list item adds a verb before the noun. Not parallel - eliminate.

This leaves us with C as the correct answer.