It is fortunate that you are able to fix the faucet because we need to use the water.?

It was fortunate that you was able

It is fortunate that you will have been able

It were fortunate that you were able

It is being fortunate that you are able

No improvement or correction is required.

That's right -- no change.

i am thinking B ?

will have been able -- is too wordy and unnecessary.

so no change ?

The correct phrase would be "It is fortunate that you were able to fix the faucet because we need to use the water."