Answer:B. Unenforceable as a violation of public policy.
Explanation: The contract which Marilyn entered with the buyer of her firm is Unenforceable as a violation of public policy. Under Normal public policy no one should be Prevented from going into any business once it is Legal and was done According to the laws of the land. In a capitalist Economy like the United States of America, private ownership of Businesses is encourage,if Marilyn finally opens a new travel agency,it will not be enforceable by the law to prevent her or stop her Business.