Need help understanding ray optics question

[Woah_Moses]

Homework Statement

http://i.imgur.com/q6EaspT.png
2. The attempt at a solution
why is the answer C? shouldn't the aperture in front of the screen create a shadow that blocks all the light except the rays that go through slit? (the width of the slit is >>>1mm so it won't make a diffraction pattern.)

 

[Dr. Courtney]

You will get diffraction through the slit but no interference pattern because the light is not coherent.

 

[lightgrav]

The answer is C , BECAUSE the aperature blocks all light except the (straight, essentially not diffracted) rays that pass thru the slit.
Did you notice that the lamp bulb was horizontally long (rather than tall)?
[that is, what would a "point source" look like on the screen? ...]