Final answer:
Delayed-onset muscle soreness (DOMS) is the correct answer as it fits the description of muscle pain appearing 12-24 hours after intense and novel resistance training, caused by microtears in the muscle fibers. So option (a) is correct.
Step-by-step explanation:
The muscle pain that is usually experienced 12-24 hours after vigorous and unaccustomed resistance training is Delayed-onset muscle soreness (DOMS). DOMS can be felt for one to three days post-exercise and generally subsides after a few days. The pain is caused by tiny tears in muscle fibers from intense physical activity.
These tears occur when muscles operate under a higher intensity than they are accustomed to, which leads to damage to the muscle fibers' sarcolemma and myofibrils. Eventually, muscles repair themselves, and gain mass through this recovery process, despite the initial discomfort caused by DOMS.
It's important to note that while DOMS is a common and generally harmless outcome of exercise, individuals with persistent or severe symptoms should consult with a healthcare professional to rule out other potential causes of muscle pain and discomfort.