One of the figures below is Farhan’s favorite figure.

Chaman and Shilpa want to figure out which is the favorite. Farhan tells Chaman the color of his favorite figure (Shilpa is aware that Chaman knows the color). Farhan tells Shilpa only the shape of his favorite figure (Chaman is aware Shilpa knows the shape). The following conversation happens.
Chaman says, “I do not know Farhan’s favorite. But I am sure that Shilpa does not know the figure either.”
Shilpa says, “At first I did not know, but now I do know Farhan’s favorite figure.”
Chaman announces, “Now I know the favorite figure too!”
Which is Farhan's favorite figure?