Answer:
c. is valid and enforceable
Step-by-step explanation:
In business, this is called a Non-Compete Clause.
Non-Compete Clause can prevent a certain individual or organization to compete with another business , as long as both parties con sensually sign the agreement.
Typically, Non-Compete clause is required after all the parties involved have some sort of affiliation toward one another/
for example:
1. One party just bought the business from another party.
2. One party is an ex-members/ex-employees of another party. Making them know internal secrets of that other party.