Support
Revive
Believe
Allow
Answer is Right!
Answer is Wrong!
The correct answer is A. Support.
To sustain something means to keep it going or to keep it from falling or collapsing. It can also mean to provide for the needs of something.
The other options are not synonyms of sustain.
B. Revive means to bring something back to life or to make something active or strong again.
C. Believe means to have faith in something or to think that something is true.
D. Allow means to give permission for something to happen.