Sentence Correction - Verbal and Reasoning

Directions to SolveWhich of phrases given below each sentence should replace the phrase printed inboldtype to make the grammatically correct? If the sentence is correct as it is, mark 'E' as the answer.
Q1:

We were still standing in the queue when the film was beginning.

A film began

B film had begun

C beginning of the film was over

D film begins

E No correction required

ANS:B - film had begun

No answer description is available.