Mineral contained in `B_(12)` is
(a) Fe
(b) Co
(c) Ni
(d) Mg

Options

A. Fe
B. Co
C. Ni
D. Mg

Answer

To determine which mineral is contained in vitamin B12, we can follow these steps:

### Step-by-Step Solution:

1. **Identify Vitamin B12**: Vitamin B12 is also known as cyanocobalamin. It is an essential vitamin that plays a crucial role in various bodily functions.

2. **Understand the Composition**: Vitamin B12 is unique among vitamins because it contains a mineral as part of its structure. This mineral is essential for its biological activity.

3. **List the Options**: The options provided are:
- (a) Iron (Fe)
- (b) Cobalt (Co)
- (c) Nickel (Ni)
- (d) Magnesium (Mg)

4. **Research the Mineral in B12**: Upon researching, it is known that vitamin B12 contains cobalt as its central atom in the structure of the vitamin. This is a key characteristic that distinguishes it from other vitamins.

5. **Eliminate Incorrect Options**:
- Iron (Fe) is not a component of vitamin B12.
- Nickel (Ni) is not involved in the structure of vitamin B12.
- Magnesium (Mg) is also not a component of vitamin B12.

6. **Conclusion**: The mineral contained in vitamin B12 is cobalt (Co). Therefore, the correct answer is option (b) Co.

### Final Answer:
(b) Co