Greg, a gambler, lives in a state where all forms of gambling are illegal. Nevertheless, Greg illegally gambled on a regular basis. Greg asked his friend, Tom, to lend him $5,000 to bet on a certain horse named Greedy Goes It. Tom agreed to lend Greg $5,000, but only if Greg would bet half of that amount ($2,500) on the same horse on Tom's behalf and split any winnings. Greg agreed to Tom's proposal, took Tom's $5,000, and placed the entire amount on the horse Greedy Goes It. Greg won on 10-10²⁻¹ odds, turning the $5,000 into $50,000. Greg then gave Tom his $5,000 back but refused to give him any additional winnings. If Tom sues Greg to recover the winnings due under his contract with Greg, who will prevail in this breach of contract lawsuit?

a) Tom, because the court will not allow Greg to profit from this contract, even though it is Greg's.
b) Greg, because his contract with Tom was illegal, and the court will not enforce an illegal contract.
c) Tom, because he fully performed his part of the contract.
d) Greg, because by returning the exact amount of money Tom loaned him, Greg did all he was legally required to do under the contract.