Weakening of limb bones may be due to deficiency of

Options

A. Riboflavin
B. Cyanocobalamine
C. Tocopherol
D. Calciferol

Explanation

To solve the question regarding the weakening of limb bones due to a deficiency, we can follow these steps:

### Step 1: Identify the Vitamins Listed
The question provides four options:
1. Riboflavin (Vitamin B2)
2. Cyanocobalamin (Vitamin B12)
3. Tocopherol (Vitamin E)
4. Calciferol (Vitamin D)

### Step 2: Understand the Role of Each Vitamin
- **Riboflavin (Vitamin B2)**: Important for energy production and cellular function, but not directly related to bone health.
- **Cyanocobalamin (Vitamin B12)**: Essential for nerve function and blood cell production, but not primarily linked to bone strength.
- **Tocopherol (Vitamin E)**: Acts as an antioxidant and supports immune function, but does not play a significant role in bone health.
- **Calciferol (Vitamin D)**: Crucial for calcium absorption in the body, which is essential for maintaining strong bones.

### Step 3: Relate the Vitamins to Bone Health
Among the vitamins listed, Vitamin D (Calciferol) is specifically known for its role in regulating calcium levels in the body. A deficiency in Vitamin D can lead to weakened bones and conditions such as rickets in children, which is characterized by soft and weak bones.

### Step 4: Conclusion
Based on the information analyzed, the weakening of limb bones is most likely due to a deficiency of **Calciferol (Vitamin D)**.

### Final Answer
The correct answer is **Calciferol (Vitamin D)**.

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