The Ministry has directed banks / to do away with their / separate promotion policies, a move / strongly opposed by the officers' unions.

Option A: "The Ministry has directed banks"
This part is grammatically correct. The verb phrase "has directed" is correctly used in the present perfect tense, and "banks" functions as the object of the verb "directed".

Option B: "to do away with their"
This is also correct. The expression "do away with" means to abolish, remove, or eliminate something. The pronoun "their" correctly refers to the banks.

Option C: "separate promotion policies, a move"
This construction is grammatically correct. The phrase "a move" refers back to the action of directing banks to eliminate their separate promotion policies.

Option D: "strongly opposed by the officers' unions"
This is also correct. The phrase "strongly opposed by" is a reduced relative clause meaning "which is strongly opposed by". The possessive form "officers' unions" is also correctly used.

Therefore, there is no grammatical error in the sentence.

Final Answer: Option E — No error