Which of the Following Agreements Is Not Supported by Consideration

Which of the following agreements is not supported by consideration?

A) Alan owes Ben £80,000. Alan cannot pay the amount and Ben agrees to discharge the debt if Alan gives him his guitar signed by John Lennon worth about £50,000.
B) David is tending his garden when he realizes that Roger's hedges bordering his lawn are uneven. He decides to even them out. Roger is so delighted when he returns home that he promises to paint David's shed when he paints his own fence.
C) Tom discovers that a wall in his apartment is rotting away and will have to be replaced. He believes the source of the leak comes from Suzanne's bathroom. Tom presents Suzanne with a bill for £550 and threatens her with a lawsuit if she does not pay. After Suzanne has paid, she is contacted by the City Council and told that the leak is coming from Dan's apartment.
D) All of the options given are correct.