Answer:
A. Isolation
Step-by-step explanation:
Isolation tackles one group of muscles, as the name suggests... in isolation.
On the contrary, compound is the use of multiple muscle groups.
In a concentric contraction, the muscle tension rises to meet the resistance then remains stable as the muscle shortens. During eccentric contraction, the muscle lengthens as the resistance becomes greater than the force the muscle is producing.
Therefore, isolation is your correct answer.