Which of the Following Sentences Would Be Most Effective in a Letter

Which of the following sentences would be most effective in a letter communicating the bad news that an employee's idea is being rejected?

A) I hope you realize that no project such as the one you propose has ever been approved here.
B) Your proposal will not be considered until you submit an accounting of all costs.
C) It is impossible to move ahead with your idea at this time because we lack the proper machinery.
D) I'm sincerely sorry, but we cannot give you the resources you need for this new project.
E) Once our budget allows for equipment upgrades, we might be able to handle this type of project.