Answer
The top of the film appears the thinnest.
Work Step by Step
We know that light reflected from the front surface of the film has a phase change due to the light reflected at the surface backed by the denser medium. The light reflected from the back surface of the film has no phase change as the light is reflected at the surface backed by the rarer medium. Thus, the light from front and back surfaces of the film undergoes destructive interference. As a result, the top of the film is thinnest and it appears black in photo.