**Core Concept**
Isovolumetric contraction phase occurs when the ventricles contract and generate force to eject blood, but the volume of blood in the ventricles remains constant due to the closed mitral and tricuspid valves. This phase is characterized by an increase in ventricular pressure without a change in volume.

**Why the Correct Answer is Right**
During isovolumetric contraction, the ventricular pressure increases rapidly due to the contraction of the ventricular muscle, but the mitral and tricuspid valves remain closed. This is because the pressure in the ventricles is lower than the pressure in the atria, preventing the valves from opening. The increase in ventricular pressure is due to the contraction of the ventricular muscle, which is mediated by the excitation-contraction coupling process involving the sarcolemma, T-tubules, and the sarcoplasmic reticulum. The correct answer correlates with the phase of the cardiac cycle when the ventricles are contracting but the volume is not changing.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the isovolumetric contraction phase. The correct answer is the phase when the ventricles are contracting and generating force, but the volume is not changing.
**Option B:** This option is incorrect because it describes the isovolumetric relaxation phase, which occurs when the ventricles are relaxing and the volume is increasing.
**Option C:** This option is incorrect because it describes the rapid ejection phase, which occurs when the ventricles are ejecting blood into the aorta and pulmonary artery.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the isovolumetric contraction phase is a critical component of the cardiac cycle, and understanding its timing and characteristics is crucial for diagnosing and managing cardiac conditions.

**Correct Answer:** C.