Select the sentence in past perfect tense: (a) I have finished my work. (b) I finished my work. (c) I had finished my work. (d) I was finishing my work

I have finished my work.

I finished my work.

I had finished my work.

I was finishing my work

The past perfect tense is formed using:

had+past participle

"had finished" → past perfect

Other options:

(a) I have finished my work. → Present perfect

(b) I finished my work. → Simple past

(d) I was finishing my work. → Past continuous