had noticed vs. noticed (conditional)

I need an explanation please.

"If I ________ the mistake, I would have corrected it.

a) would have noticed
b) had noticed
c) noticed

and why?

A is wrong because the if-clause that goes with a main clause “would” should not have “would” itself in a sentence such as this.

C is impossible because of context: you cannot notice the mistake after you correct it; the tense in would have corrected takes place before that in noticed.

B is right: noticing and correcting both took place at roughly the same time.

Make sense to me… Thanks Cerberus! It’s all because of you teachers that I get stuck in mostly.

OK don’t mention it. You “get stuck in”?

I meant now I stay here quite often. I know I was wrong, so that you could advice me.

Ha! Good one. You could say “that’s why I stick around”.
And you should have said “advise”: advice is not a verb.