[A]: Genes confined to differential region of homologous chromosomes are called holandric genes.
[R]: Genes confined to homologous region of Y chromosomes only are celled Holandric genes.

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 solve the question, we need to analyze the statements provided and determine their validity.

### Step-by-Step Solution:

1. **Understanding Assertion [A]:**
- The assertion states that "genes confined to the differential region of homologous chromosomes are called holandric genes."
- **Analysis:** Holandric genes are specifically associated with the Y chromosome, not just any homologous chromosomes. Therefore, this statement is incorrect.

2. **Understanding Reason [R]:**
- The reason states that "genes confined to homologous region of Y chromosomes only are called Holandric genes."
- **Analysis:** Holandric genes are located in the differential region of the Y chromosome, which is not the same as the homologous region. Thus, this statement is also incorrect.

3. **Conclusion:**
- Both the assertion [A] and the reason [R] are false. Therefore, the correct answer is that both statements are false.

### Final Answer:
Both [A] and [R] are false.