Choose the correct passive voice: "The bank had frozen the account before the investigation began."
- A. The account was frozen by the bank before the investigation began.
- B. The account had being frozen by the bank before the investigation began.
- C. The account had been frozen by the bank before the investigation began. ✓
- D. The account has been frozen by the bank before the investigation began.
Correct answer
C. The account had been frozen by the bank before the investigation began.
Explanation
Past perfect active becomes past perfect passive: 'had been frozen'.