We must endure what we cannot cure.

Options

A. What cannot cured must endured.
B. What could be cure must be endured.
C. What we cure must be endured.
D. What cannot be cured must be endured.

Answer

D

Explanation

What cannot be cured must be endured. (Passive)
The sentence is in Simple Present Tense. (Active)
It is case of Double Passive. Modals (can, must) in Active changes to can be, must be in Passive.