**Core Concept**
Capacitation is a physiological change that spermatozoa undergo in the female reproductive tract, allowing them to fertilize an egg. This process involves changes in the sperm membrane, including increased permeability to calcium ions, which is essential for the acrosome reaction and subsequent fertilization.

**Why the Correct Answer is Right**
The correct answer is B. Decreased permeability to calcium. During capacitation, the sperm membrane undergoes changes that increase its permeability to calcium ions (Ca2+). This increase in calcium influx is crucial for the initiation of the acrosome reaction, which enables the sperm to penetrate the egg's outer layers. The correct answer, B. Decreased permeability to calcium, is incorrect because capacitation involves an increase in calcium permeability, not a decrease.

**Option A:** Increased permeability to calcium is the correct process that occurs during capacitation, making this option incorrect because it is already stated in the correct answer.
**Option C:** The acrosome is a cap-like structure at the tip of the sperm head, but the process of capacitation involves changes to the sperm membrane, not the removal of cholesterol from the acrosome.
**Option D:** Increased motility is a characteristic of capacitated sperm, but it is not a change that occurs during capacitation itself; rather, it is a result of the capacitation process.

**Clinical Pearl / High-Yield Fact**
Capacitation is a necessary step for sperm to fertilize an egg, and any factors that disrupt this process, such as certain medications or infections, can lead to infertility. Understanding the biochemical changes that occur during capacitation is essential for the development of new fertility treatments.

✓ Correct Answer: B. Decreased permeability to calcium