Step 1: Read the document carefully.
A sells his house to B for 5,00,000, but adds a condition in the same paper: if A repays the money within 3 years, B must give the house back; if A fails, the sale becomes absolute. A fails to repay. We must find the true legal nature of this deal under the Transfer of Property Act, 1882.
Step 2: Spot the special feature.
This is not a plain sale. There is a repayment option and a reconveyance promise, all written in one document. This pattern has a specific legal name.
Step 3: Apply Section 58(c).
Section 58(c) defines a mortgage by conditional sale. It applies when an owner ostensibly sells property on the condition that, on default of payment, the sale becomes absolute, with a promise to reconvey if payment is made.
Step 4: Note the same document rule.
The proviso to Section 58(c) is important: it is a mortgage only if the condition is contained in the same document that effects the sale. Here the condition is in the same document, so it is a mortgage by conditional sale, not an outright sale.
Step 5: What happens on default?
Because it is a mortgage, B does not automatically become the absolute owner when 3 years pass. To get full ownership, B (the mortgagee) must file a suit for foreclosure as the Act requires.
Step 6: Eliminate the wrong options.
Option B (void for uncertainty) is wrong because the terms are clear. Option C (outright sale, automatic ownership) is wrong because it is really a mortgage. Option D (lease with repurchase) is wrong because there is no lease here. So B, C, and D fail.
Step 7: Final answer.
It is a mortgage by conditional sale, and B must seek foreclosure through court.
\[ \boxed{\text{It is a mortgage by conditional sale; B must seek foreclosure through court.}} \]