Watson helped Henry study all night for an important exam. After Henry got an $A$ on the exam, he told Watson, I will give you $$10$ for helping me get a good grade. Watson said, Thanks, I'll take it$.$ There is:

Select one:

a$.$ no contract because $$10$ is reasonably inadequate consideration.

b$.$ no contract because there is no valid consideration.

c$.$ no contract because there is no mutual assent.

d$.$ a contract with sufficient consideration.