Abbey helped Greyson study for an important exam for about $8$ hours. After Greyson got an $"$A$"$ on the exam, he told Abbey, "I will give you $$25$ for helping me get a good grade." Abbey said, "Thanks, I'll take it$."$ There is:

Group of answer choices

a contract with sufficient consideration.

no contract because there is no valid consideration.

no contract because there is no mutual assent.

no contract because $$25$ is not adequate consideration for $8$ hours work.