From the words or groups of words lettered A to D, chose the word or group of words that best completes the sentence. Mary said she was acting ... the instr...

Answer Details

The word that best completes the sentence "Mary said she was acting ... the instructions of the principal" is "on". The sentence implies that Mary was taking some action, and she was doing so based on the instructions of the principal. In this context, the word "on" means "according to" or "based on", which indicates that Mary was acting in accordance with the principal's instructions. The words "by", "for", and "through" do not convey the same meaning as "on" in this context.