Which of Following Is the Best Way to Begin a Message

Which of following is the best way to begin a message refusing a request for the free use of equipment for a charity?

A) We have already loaned our equipment to other charitable organizations.
B) We wish we could help you because the youth are clearly benefiting from your efforts.
C) This is to inform you that our equipment cannot be loaned at this time.
D) Thank you for letting us know about the important work your center is doing for our city.
E) Although we would like to grant your request, we are not able to do so at this time.