Mahesh (who is colourblind) and soni (who is not colourblind have q daughter Alia. Rish ( who is not colourblind) and Neetu (who is a carrier ) have a son Ranbeer . Alia and Ranbeer get married . What is the probability that their daughter will be colourblind ?

Options

A. `0%`
B. `25%`
C. `50%`
D. `75%`

Answer

To solve the problem step by step, we need to analyze the genetic information provided about Mahesh, Soni, Alia, Rishi, Neetu, and Ranbeer. We will use a Punnett square to determine the probability of Alia and Ranbeer’s daughter being colorblind.

### Step 1: Determine the genotypes of Mahesh and Soni
- Mahesh is colorblind, which means he has the genotype X^cY (where X^c represents the colorblind allele).
- Soni is not colorblind, so her genotype is XX (homozygous normal).

### Step 2: Determine the genotype of Alia
Using a Punnett square for Mahesh (X^cY) and Soni (XX):
```
X X
---------------
X^c | X^cX | X^cX |
---------------
Y | XY | XY |
```
From this, we see that:
- All daughters (Alia) will have the genotype X^cX (carrier).

### Step 3: Determine the genotypes of Rishi and Neetu
- Rishi is not colorblind, so his genotype is XY.
- Neetu is a carrier, so her genotype is X^cX.

### Step 4: Determine the genotype of Ranbeer
Using a Punnett square for Rishi (XY) and Neetu (X^cX):
```
X^c X
----------------
X | XX | XY |
----------------
Y | X^cY | XY |
```
From this, we see that:
- Ranbeer can either be XY (normal) or X^cY (colorblind).

### Step 5: Determine the probability of Alia and Ranbeer’s daughter being colorblind
Now we need to consider the possible combinations when Alia (X^cX) and Ranbeer (XY or X^cY) have children.

1. If Ranbeer is XY (normal):
```
X^c X
----------------
X | XX | XY |
----------------
Y | X^cY | XY |
```
- All daughters will be XX (normal) or X^cX (carrier). None will be colorblind.

2. If Ranbeer is X^cY (colorblind):
```
X^c X
----------------
X^c | X^cX | X^cX |
----------------
Y | X^cY | XY |
```
- The daughters can be X^cX (carrier) or X^cX (colorblind).

### Step 6: Calculate the probability
- If Ranbeer is XY, the probability of their daughter being colorblind is 0%.
- If Ranbeer is X^cY, the probability of their daughter being colorblind is 50%.

### Final Calculation
Since Ranbeer has a 50% chance of being colorblind (X^cY) and a 50% chance of being normal (XY), we can average the probabilities:
- Probability of daughter being colorblind = (0% * 0.5) + (50% * 0.5) = 25%.

### Conclusion
The probability that Alia and Ranbeer’s daughter will be colorblind is **25%**.