Deficiency of which vitamin present classically as 3 ‘Ds’-
**Core Concept**
The question refers to a vitamin deficiency that classically presents with three distinct symptoms, often remembered as the '3 Ds'. This condition is related to a lack of a specific vitamin that plays a crucial role in the nervous system and muscle function. The underlying principle involves the role of vitamins in maintaining neurological health.
**Why the Correct Answer is Right**
Although the correct answer option is missing, the description fits a vitamin deficiency that affects the nervous system, leading to symptoms such as diarrhea, dermatitis, and dementia. This condition is associated with a lack of **niacin (Vitamin B3)**, which is essential for converting food to energy by contributing to the formation of **NAD** and **NADP**. These coenzymes are vital for cellular metabolism.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not match the classic '3 Ds' symptoms associated with the described vitamin deficiency.
**Option B:** Similarly, this option does not align with the condition characterized by the '3 Ds'.
**Option C:** This option is also incorrect as it does not correspond to the vitamin deficiency leading to the '3 Ds' symptoms.
**Clinical Pearl / High-Yield Fact**
The '3 Ds' of vitamin deficiency (diarrhea, dermatitis, and dementia) are classic symptoms of **pellagra**, a condition caused by **niacin (Vitamin B3) deficiency**. Recognizing these symptoms is crucial for early diagnosis and treatment.
**Correct Answer:** D. Niacin.