Select the correct passive form of the given sentence.
Somebody has already tipped the custom authorities about the drugs.

Options

A. Custom authorities have already tipped someone about the drugs.
B. Custom authorities have already been tipped about the drugs.
C. Custom authorities have already been tipped by the drugs
D. Custom authorities were already tipped about the drugs.

Explanation

(b) Custom authorities have already been tipped about the drugs. (Correct)(a) Custom authorities have already tipped someone about the drugs. (Tense has changed) (c) Custom authorities have already been tipped by the drugs . (Incorrect Tense and Structure) (d) Custom authorities were already tipped about the drugs. (Tense has changed)