Answer:
b. the difference between Solomon's contract price and the amount paid by Renny
Explanation:
Neal sues Solomon for damages as Solomon breaches his contract with Neal to purchase the 500 pairs of socks from him. Although he can sell the 500 pairs to Renny even then he was in loss only as he sells socks to Renny at a lower amount then it's actual cost.
In this case, Neal will be able to recover the difference between Solomon's contract price and the amount paid by Renny.