**Core Concept:** Ferning is a method used in obstetrics to evaluate cervical mucus's consistency in predicting ovulation and fertility. The process involves observing the mucus under a microscope to determine if it is optimal for facilitating sperm penetration and egg fertilization.

**Why the Correct Answer is Right:** Ferning is a crucial aspect of cervical mucus evaluation, as it assesses the mucus's consistency and appearance, which can help predict ovulation and fertility. In this case, the correct answer is C, which states that ferning depends on the presence of proteins, especially glycoproteins.

**Why Each Wrong Option is Incorrect:**

A. Ovulation does not solely depend on cervical mucus ferning. Other factors, such as hormonal levels, are also crucial for fertility assessment.

B. Although cervical mucus undergoes changes during the menstrual cycle, the ferning process does not solely rely on mucus pH. Various other factors contribute to mucus's fertility-predictive properties.

D. The ferning process is not solely determined by the mucus's consistency. Other aspects, like mucus composition and hormonal levels, also play significant roles in predicting ovulation and fertility.

**Clinical Pearl / High-Yield Fact:** Monitoring cervical mucus ferning is essential for fertility prediction and assisted reproductive techniques like in vitro fertilization (IVF). A positive ferning pattern indicates increased fertility potential, while an abnormal pattern may signal hormonal imbalances.

**Correct Answer:** C. Presence of proteins, especially glycoproteins.

**Why the Correct Answer is Right:** Ferning is a method used to evaluate cervical mucus consistency, which is an essential component of predicting ovulation and fertility. The presence of proteins, particularly glycoproteins, plays a significant role in the formation of the characteristic net-like structures when water is added, which is important for sperm penetration and fertilization to occur.