Who does Karim decide to create his second character for the acting troupe assignment on, and what dilemma does that bring about?

When Karim is asked to create his character for the acting troupe on someone other than Anwar, he decides to use Changez. At first, Changez thinks its a good idea, but after he and Karim have a disagreement about Jamila,, Changez asks him not to base the character on him. This creates a moral dilemma for Karim regarding whether or now he should still use Changez as the muse for his character, or if he should respect Changez's request and avoid betraying him for the second time.