Which of the following promises constitutes sufficient consideration in the formation of a contract?
A.
To reimburse the cost of refurbishing a house where the promise in made after the refurbishing has been completed
B.
To lease a house at an annual rent significantly below current market rates
C.
To pay a witness an agreed monetary sum in exchange for attending court
D.
To pay a worker extra remuneration in exchange of continuing to perform their existing contractual duties