**Core Concept**
Pitting of nails is a dermatological manifestation that is often associated with systemic conditions, particularly autoimmune disorders and nutritional deficiencies. It is characterized by small, round depressions on the surface of the nails, which can be a sign of underlying disease.

**Why the Correct Answer is Right**
Pitting is thought to occur due to the separation of the nail plate from the nail bed, which is often a result of inflammation and damage to the nail matrix. In conditions such as psoriasis, the nail matrix is affected by an autoimmune response, leading to the formation of pits. The nail matrix is the area beneath the cuticle where the nail plate is produced, and damage to this area can result in the characteristic pitting seen in conditions like psoriasis.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because pitting is not typically associated with fungal infections, which are more commonly characterized by discoloration, thickening, and brittleness of the nails.

**Option B:** This option is incorrect because pitting is not a typical feature of bacterial infections, which can cause a range of symptoms including redness, swelling, and pus.

**Option C:** This option is incorrect because while nutritional deficiencies can cause changes in the nails, such as brittleness or discoloration, pitting is not a characteristic feature.

**Clinical Pearl / High-Yield Fact**
Pitting of the nails is often associated with psoriasis, and it can also be seen in other autoimmune conditions such as alopecia areata and lichen planus. It is an important clinical finding that can help diagnose underlying disease.

**Correct Answer:** C.