15h

I think it can be accepted bcoz 197A states that:

no deduction of tax shall be made if individual furnishes a declaration in writing in duplicate in the prescribed form and verified in the prescribed manner to the effect that the tax on his estimated total income of the previous year in which such income is to be included in computing his total income will be nil.

So what one can interpret from the above is that if tax on income is nil, then form 15H/G can be accepted.