Step 1: Understanding the word "recuperate."
"Recuperate" means to recover or regain health after an illness or injury. The antonym should describe a process of worsening or declining in health or condition.
Step 2: Analyzing the options.
- Resuscitate means to revive someone from unconsciousness or apparent death, which is the opposite of death but not the opposite of recuperating.
- Reimburse means to pay someone back, unrelated to health recovery.
- Degenerate means to decline or deteriorate, which is the correct antonym of recuperate, as it suggests a worsening of condition.
- Convalesce means to recover or regain strength, which is the opposite of declining health and not the correct antonym.
Step 3: Conclusion.
"Degenerate" is the correct antonym, as it means to decline in health or condition.
Thus, the correct answer is 3. Degenerate.
Final Answer:
\[
\boxed{\text{The correct answer is 3. Degenerate.}}
\]