[A]: Metacentric chromosomes are V- shaped.
[R]: In these chromosomes the centromere occurs in the centre and forming two equal arms.

Options

A. If both A and R are true and R is the correct explanation of A
B. If both A and R are true but R is not the correct explanation of A
C. If A is true and R is false
D. If both A and R are false

Answer

To analyze the given statements about metacentric chromosomes, we will break down the assertion and reason step by step.

### Step-by-Step Solution:

1. **Understanding Metacentric Chromosomes**:
- Metacentric chromosomes are characterized by the position of the centromere. The centromere is located at the center of the chromosome.
- This central placement results in two arms of equal length on either side of the centromere.

2. **Assertion Analysis**:
- The assertion states that "metacentric chromosomes are V-shaped."
- This is somewhat misleading. While metacentric chromosomes can appear V-shaped during certain stages of cell division (specifically during anaphase of mitosis), they are not inherently V-shaped in their resting state. They are typically X-shaped due to the two chromatids being joined at the centromere.

3. **Reason Analysis**:
- The reason states that "in these chromosomes the centromere occurs in the center, forming two equal arms."
- This statement is true. The centromere's central position does indeed create two equal arms, which is a defining characteristic of metacentric chromosomes.

4. **Conclusion**:
- Both the assertion and the reason are true statements. However, the assertion's description of metacentric chromosomes as V-shaped is not accurate in a general sense; it is only during specific phases of cell division that they may appear V-shaped.
- Therefore, while both statements are true, the reason does not correctly explain the assertion in its entirety.

### Final Answer:
- The answer is: A is true, R is true, but R is not the correct explanation of A.