Beri-beri is debility due to deficiency of
(a) Biotin
(b) Thiamine
(c) Riboflavin
(d) Nicotinamide

Options

A. Biotin
B. Thiamine
C. Riboflavin
D. Nicotinamide

Answer

To solve the question regarding the cause of beriberi, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks about the condition known as beriberi and which nutrient deficiency causes it.

2. **Identify the Options**: The options provided are:
- (a) Biotin
- (b) Thiamine
- (c) Riboflavin
- (d) Nicotinamide

3. **Research Each Option**:
- **Biotin**: This vitamin is important for fatty acid synthesis and energy metabolism but is not related to beriberi.
- **Thiamine**: This is Vitamin B1, which is essential for carbohydrate metabolism and nerve function. A deficiency in thiamine leads to beriberi.
- **Riboflavin**: This is Vitamin B2, which plays a role in energy production and cellular function but is not associated with beriberi.
- **Nicotinamide**: This is a form of Vitamin B3, important for DNA repair and metabolism, but not linked to beriberi.

4. **Conclusion**: After evaluating the options, it is clear that beriberi is caused by a deficiency of thiamine (Vitamin B1).

5. **Final Answer**: The correct answer is (b) Thiamine.