And why is C?
being is not supposed to be always wordy?
I was with D, but was wrong
If you join two sentences with "and" and you don't use a comma, then you can't repeat the subject
Peter ate an apple and drank water. Correct
Peter ate an apple and he drank water. Incorrect
Peter ate an apple, and he drank water. Correct.
Another problem with D is the end of the sentence
there is an increasing view by the military as a threat to security
what is viewed as a threat to security?
I believe this doesn't make any sense