In part two of trifles which of the following is an example of dramatic irony?

I believe the choices are the below. The answer is C.

a. The women find that Mrs. Wright was stitching a quilt with a log-cabin design.

b. The men believe that Mrs. Wright may not have been a very good homemaker.

c. The audience knows about the deceased bird hidden in the box, but the men in the play do not.

d. The audience views the setting of the Wright home as a lonely place, but the characters do not.