As per the definition of Contingent Contract under the Indian Contact Act which of the following is an example of contingent contract?

Priya enters into a contract with Payal to pay her Rs. 10,000 if the books are delivered to her on Monday, Explanation: Contract Act Section 31 -If two or more parties enter into a contract to do or not do something, if an event which is collateral to the contract does or does not happen, then it is a contingent contract. So as per this definition and the above examples (b) is the correct option as in that case delivery of books by Monday is collateral to the contract and not a part of the consideration. Hence, this is a contingent contract.