Given below are Legal Principles followed by a Factual Situation. Apply the principles followed by a factual Situation. Apply the principle to it and select the most appropriate answer for question among the four choices given.
LEGAL PRINCIPLE: An agreement is void and unenforceable if considerations and objects are unlawful.
FACTUAL SITUATION: A enters into an agreement with B for ten countrymade pistols and ten landmines. A promises to pay a sum of Rs. 2,50,000 to B. He paid 75,000 in advance. On completing the work and handing over the materials as required, A refuses to pay the remaining sum of Rs. 1,75,000 to B.
DECIDE.