Answer:
It is a Unilateral Contract.
Step-by-step explanation:
A unilateral contract is when one of the parties in a contract reserves the right to cancel the transaction. The cancellation is usually based on performance, and when expectations are not met the contract can be terminated.
In this case the buyer has the unilateral right to cancel the transaction within 10 days if he is not satisfied.
Bilateral contract on the other hand involves two parties making promises to meet their respective obligations.