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 instructions of the principal.
A
by
B
on
C
for
D
through
Verified Correct Answer: B.
Grammar & Contextual Explanation
So, the completed sentence is:
"Mary said she was acting on the instructions of the principal."
"Acting by" could suggest proximity or means.
"Acting for" could imply acting on behalf of someone.
Acting through" suggests a process or medium.
"On" is the correct preposition to use when referring to following or acting according to instructions. Therefore, B. on is the correct answer.
Source: Myschool Past Questions Archive (Record #23380)