We can see here that the theme the monster most clearly convey is: C. Losing control and giving in to instinct.
What is theme?
A work of literature, art, music, or another form of expression may have a fundamental idea or message that it wants to get over. It is a universal subject or problem that is examined in a work and that the reader or viewer can interpret.
The plot, characters, setting, and other aspects of the work can all be used to represent themes, which can be either apparent or implicit.
A theme is distinct from a subject or topic, which refers to the particular subject matter or content of a work.
The complete question is:
Read this description:
The werewolf, an ordinary man who changes into a wolf-like creature upon every full moon, goes berserk every time he transforms and starts hunting people like an animal.
Which theme does this monster most clearly convey?
A. Belief that might makes right
B. Fear of repressive regimes
C. Losing control and giving in to instinct
D. Belief in the supernatural