**Core Concept**
The cardiac cycle is divided into several phases, each with distinct physiological characteristics. The left ventricle's pressure varies significantly throughout the cycle, influenced by the interplay of contractility, preload, and afterload. Understanding the pressure dynamics in different phases is crucial for grasping cardiac physiology.

**Why the Correct Answer is Right**
During ventricular ejection, the left ventricle contracts and pushes blood into the aorta, resulting in a significant increase in pressure. This phase is characterized by a rapid rise in pressure, often referred to as the "pressure peak." The pressure in the left ventricle reaches its maximum value during ventricular ejection due to the combined effects of contractility and the reduction in ventricular volume. The ventricular ejection phase is a critical period where the left ventricle generates the highest pressure to overcome the systemic vascular resistance and eject blood into the circulation.

**Why Each Wrong Option is Incorrect**
**Option A:** Isovolumetric contraction is the initial phase of ventricular contraction, where the ventricular pressure increases without a change in volume. Although pressure does rise, it does not reach its maximum value during this phase.
**Option C:** Protodiastole marks the beginning of diastole, where the ventricular pressure rapidly decreases as the ventricle relaxes. It is the opposite of the ventricular ejection phase, where pressure is increasing.
**Option D:** Rapid ventricular filling occurs during early diastole, where the ventricle rapidly fills with blood. The pressure in the left ventricle is low during this phase, as the ventricle is relaxing and accommodating the incoming blood.

**Clinical Pearl / High-Yield Fact**
The maximum pressure in the left ventricle is a critical factor in determining the cardiac output and peripheral resistance. A significant increase in left ventricular pressure during ventricular ejection is essential for maintaining adequate blood pressure and perfusion of vital organs.

**✓ Correct Answer: B. Ventricular ejection**