Which of the following statements are true for complementary genes?
(a)Both the genes interact to produce complementary new trait
(b) Pair of non-allelic genes
(C )The `F_(2)` ratio is generally 9:7
(d)The `F_(2)` ratio is generally 9:3:4

Options

A. (a),(b) and (C ) are true
B. (a) and (b) are true
C. (b) and (c )are true
D. (C )and (d)are true

Answer

To determine which statements are true for complementary genes, let's analyze each statement step by step.

### Step-by-Step Solution:

1. **Understanding Complementary Genes**:
- Complementary genes are defined as two or more non-allelic genes that work together to produce a specific trait. When both genes are present, they produce a new phenotype that is not seen when either gene is absent.

2. **Evaluating Statement (a)**:
- **Statement (a)**: "Both the genes interact to produce complementary new trait."
- This statement is **true**. Complementary genes indeed interact to produce a new trait that is not expressed when either gene is present alone.

3. **Evaluating Statement (b)**:
- **Statement (b)**: "Pair of non-allelic genes."
- This statement is also **true**. Complementary genes are non-allelic, meaning they are located on different loci and do not compete for the same allelic position.

4. **Evaluating Statement (c)**:
- **Statement (c)**: "The F2 ratio is generally 9:7."
- This statement is **true**. In a dihybrid cross involving complementary genes, the phenotypic ratio in the F2 generation is typically 9:7, indicating that both genes need to be present for the dominant phenotype to be expressed.

5. **Evaluating Statement (d)**:
- **Statement (d)**: "The F2 ratio is generally 9:3:4."
- This statement is **false**. The 9:3:4 ratio is characteristic of recessive epistasis, not complementary gene interaction.

### Conclusion:
Based on the evaluations:
- The true statements are (a), (b), and (c).
- The false statement is (d).

### Final Answer:
The correct statements regarding complementary genes are:
- (a) True
- (b) True
- (c) True
- (d) False