Fred Owes Amy £100 but Has Failed to Pay It

Fred owes Amy £100 but has failed to pay it for months. One day, Amy sees Fred at the bank. Fred is withdrawing £90. Amy reminds him of the debt. Fred agrees to pay Amy £90 if she stops whining about the remaining £10. Which of the following statements is TRUE?

A) This agreement lacks consideration and is unenforceable since Amy is agreeing to accept less for the same. Amy can claim the remaining £10.
B) This agreement may be supported by consideration since Amy may have a practical benefit in accepting £90 instead of £100, in which case she would be unable to go back on her promise and claim the remaining £10.