The number of films that present social commentary of some kind has increased recently, probably because of an understanding that films of this nature are often the recipients of profuse media interest.
A. has increased recently, probably because of an understanding that
films of this nature are often the recipients of IncorrectB.
had increased recently, probably because of an understanding that such films often receive
IncorrectC.
increased recently, probably because of an understanding that such films often receive
IncorrectD. has increased recently, probably because of an understanding that such films
had often received IncorrectE.
has increased recently, probably because of an understanding that such films often receive CorrectPOE -
recently uses in sentence, so sentence should not be in past form; eliminate B & C
In D understanding in past form that is illogical
In A this refers to what? and a is wordy
E is better and concise