Answer:
He acts like he's going to cry. C.
Complete sentence. The comma is used the right way so it wouldnt be a comma splice, and if you replaced the comma with a period it would be wrong, so not a run on. That is why it is a complete sentence
This is an example of a simile, a comparison between two things using the words "like" or "as." "Gloomy as the night" is the simile here, since his sadness is being compared to nighttime.
