✔ Correct Answer: C. I had been working since 2 O’clock.

The correct answer to the question “Choose the correct sentence: I had been working for 2 O’clock., I was working since 2 O’clock., I was working for 2 O’clock., I had been working since 2 O’clock.” is I had been working since 2 O’clock.. This question belongs to Grammar Concepts & Terms in English. Practice the related questions below to master this topic for your FPSC, PPSC and NTS tests.