Cobalt as a rare element is essential in the synthesis of this vitamin.

Options

A. Vitamin C
B. Vitamin D
C. Vitamin `B_(1)`
D. Vitamin `B_(12)`

Answer

To solve the question regarding which vitamin requires cobalt for its synthesis, we can follow these steps:

### Step 1: Identify the vitamins mentioned
We need to consider the vitamins that are commonly known and check if they are associated with cobalt. The vitamins mentioned in the video are:
- Vitamin C (ascorbic acid)
- Vitamin D
- Vitamin B1 (thiamine)
- Vitamin B12 (cobalamin)

### Step 2: Analyze the role of cobalt in vitamin synthesis
Cobalt is a metal that is known to be essential for the synthesis of certain compounds. In the context of vitamins, we need to determine which vitamin contains cobalt as part of its structure.

### Step 3: Evaluate each vitamin
- **Vitamin C (ascorbic acid)**: Does not require cobalt for its synthesis.
- **Vitamin D**: Also does not involve cobalt in its synthesis.
- **Vitamin B1 (thiamine)**: This vitamin does not contain cobalt either.
- **Vitamin B12 (cobalamin)**: This vitamin is unique because it contains cobalt as part of its molecular structure.

### Step 4: Conclude the answer
Based on the analysis, the only vitamin that requires cobalt for its synthesis is **Vitamin B12 (cobalamin)**.

### Final Answer:
Cobalt is essential in the synthesis of **Vitamin B12**.

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