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.

I had been working for 2 O’clock.

I was working for 2 O’clock.

I had been working since 2 O’clock.

None of these

I had been working since 2 O’clock.

"Had been working" is past perfect continuous tense.

It is used to show an action that started in the past and continued up to another point in the past.

"Since" is used with a specific point in time (like 2 O’clock).