What one must do, one must do properly.

Options

A. What must be done, must be done properly.
B. It must be done properly what one must do.
C. It must be done what one must do properly.
D. One must do properly what has to be done.

Answer

A

Explanation

What must be done. must be done properly. (Passive)
The sentence is in Simple Present Tense. (Active). It is also a complex sentence.

When a Modal is used in Active, the Passive form will be as follows : Modal +be +Past Participle of the Verb.
In changing the voice of Complex Sentences, the voice of both the Principal Clause (one must do properly) and Sub-ordinate Clause (what one must do) should be changed.