**Core Concept**
Relaxation of skeletal muscle involves the cessation of muscle contraction, which is primarily governed by the regulation of calcium ions (Ca²⁺) within the muscle cell. The process relies on the interaction between the sarcoplasmic reticulum (SR) and the T-tubule system.

**Why the Correct Answer is Right**
Relaxation of skeletal muscle occurs through the reuptake of calcium ions (Ca²⁺) into the sarcoplasmic reticulum (SR), a process mediated by the calcium pump (SERCA). This reduces the concentration of free Ca²⁺ ions in the cytosol, which in turn decreases the activity of the troponin-tropomyosin complex, allowing the muscle to relax. The T-tubule system plays a crucial role in the regulation of calcium ion flow during muscle relaxation.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the relaxation of skeletal muscle.
**Option B:** This option may be related to muscle contraction, but it does not accurately describe the process of muscle relaxation.
**Option C:** This option is incorrect as it refers to a different physiological process.

**Clinical Pearl / High-Yield Fact**
During muscle relaxation, the sarcoplasmic reticulum (SR) acts as a calcium ion reservoir, rapidly reuptaking Ca²⁺ ions to terminate muscle contraction. Understanding the role of the SR in muscle relaxation is crucial for diagnosing and managing conditions like malignant hyperthermia.

**Correct Answer: C.**