It is highly desirable that you furnish evidence of your expenses before you submit your final accounts.

A. It is highly desirable that you furnish evidence of your expenses
B. It is highly desirable that you should furnish evidence of your expenses
C. It is highly to be desired that you furnish evidences of your expenses
D. You must furnish evidence of your expenses
E. You should have to supply evidence of your expenses


why not D?? pity straight forward