Mr krishna,
Definitely deduction u/s 80 c will be available to Mrs A
As per section 80c Payments made during the previous year towards the cost of purchase/construction
of new residential house property the income from which is chargeable under the head 'income from house property are eligible for deduction under section 80C.
And as per income tax act the existence of a building is an essential perquisite. Building will, of course, include residential house (whether let out or self occupied),office building, factory building, godowns, flats, etc. as long as they are not used for business or profession by owner. It means owner of the building may let out his house property for any purpose but it should not be used for business and profession carried on by him. Therefore property can be let out for any purpose. And the purpose for which the building is used by the tenant is also immaterial.
So even Mrs A has let out her residential property for business purpose still that property will fall under the head 'income from house property' and income from that will be chargeable under that head also.
Therefore deduction u/s 80c will be allowed definitely.
I hope this will help you.