QUESTION 2 - Please answer (a) and (b) separately

On 3/15/09, A orally agrees to pay $500 in return for B's providing snow plowing services for the 2000-1 season from 11/1/09 to 4/1/10. On 10/15/09, B sends a letter to A stating that due to the breakdown of his truck, the prior oral agreement (terms are stated) is canceled. A does not reply, but hires C's snowplow service agreeing orally to pay $600. At the end of the season, A pays C the $600 and sues B for the additional $100 expense.

2a. Who wins, how much, and WHY?

2b. Discuss all appropriate rules of law raised by this question.