In an adjustment-grant message, which of the following sentences offers the best lead into the explanation of what went wrong?
a) We sincerely regret the inconvenience caused you and want to explain what happened.
b) Because we want very much to please you, we carefully inspected the machine that caused the trouble.
c) A review of the facts surely supports our contention that the machine was not at fault.
d) As your satisfaction with our product is important to us, we thoroughly checked the machine.
e) Inspection of the machine clearly reveals the source of the problem.