In protanopia ,a person cannot distinguish

Options

A. Green colour
B. Red colour
C. Blue colur
D. Blue and green colour

Answer

### Step-by-Step Solution:

1. **Understanding Protanopia**: Protanopia is a type of color blindness that affects a person's ability to perceive certain colors. It is specifically related to the sensitivity of the red cones in the eye.

2. **Cone Types**: Humans typically have three types of cone cells in their retinas, which are sensitive to different wavelengths of light. These cones are responsible for color vision and are known as S (short wavelength, blue), M (medium wavelength, green), and L (long wavelength, red) cones.

3. **Effect of Protanopia**: In individuals with protanopia, there is a reduced sensitivity to red light due to the malfunctioning of the L cones. This means that they have difficulty distinguishing red from other colors.

4. **Identifying the Color Distinction**: Since protanopia primarily affects the perception of red light, individuals with this condition will struggle to differentiate between red and other colors, particularly green.

5. **Conclusion**: Therefore, the correct answer to the question "In protanopia, a person cannot distinguish" is **red color**.