Select the option that expresses the given sentence in passive voice.

The police had collected the primary evidence before they arrested the culprit.

A

The primary evidence had been collected by the police before the culprit was arrested.

B

The primary evidence had collected by the police before the culprit was arrested.

C

The primary evidence might have been collected by the police before the culprit was arrested.

D

The primary evidence was collected by the police before the culprit was arrested.