A colour blind daughter is born in case of

Options

A. Colour blind mother normal father
B. Carrier mother colour blind father
C. Normal mother colour blind father
D. Carrier mother normal father

Answer

### Step-by-Step Solution:

1. **Understanding Colorblindness**:
- Colorblindness is a genetic disorder that is inherited in an X-linked recessive manner. This means that the gene responsible for colorblindness is located on the X chromosome.

2. **Identify the Genetic Makeup**:
- Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). For a female to be colorblind, she must inherit two copies of the colorblind allele (one from each parent) or be a carrier (one normal X and one colorblind X).

3. **Analyzing the Options**:
- **Option A**: Colorblind mother and a normal father.
- A colorblind mother (XcXc) can only pass on Xc to her daughters, leading to colorblind daughters. However, a normal father (XY) cannot contribute a colorblind allele.
- **Option B**: Carrier mother and a colorblind father.
- A carrier mother (XXc) can pass on either a normal X (X) or the colorblind X (Xc). The colorblind father (XcY) can only pass on the Xc. This combination can produce colorblind daughters.
- **Option C**: Normal mother and a colorblind father.
- A normal mother (XX) can only pass on normal Xs, resulting in no colorblind daughters.
- **Option D**: Carrier mother and normal father.
- A carrier mother (XXc) can pass on either a normal X or a colorblind X, but a normal father (XY) cannot contribute a colorblind allele, leading to no colorblind daughters.

4. **Conclusion**:
- The only scenario that can lead to the birth of a colorblind daughter is **Option B: Carrier mother and a colorblind father**. This is because the carrier mother can pass on the colorblind allele (Xc), and the colorblind father can only pass on his colorblind allele (Xc).

### Final Answer:
- The correct answer is **Option B: Carrier mother and a colorblind father**.

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