Answer:
A) in response to an increase in the cytoplasmic Ca2+concentration.
Explanation:
Muscle contraction occurs in response to an increase in the cytoplasmic Ca2 + concentration.
This process occurs with the shortening of the sarcomeres resulting in a result, the actin filaments react with myosin, generating actomyosin. During this reaction, it is necessary to increase the cytoplasmic concentration of Ca + and ATP. In this, myosin will break down ATP, releasing energy so that the muscle can contract.