**Core Concept**
The person's condition is related to a defect in the perception of blue color, which is a form of color vision deficiency. This is due to a problem with the retina, specifically the cone cells responsible for detecting blue light.

**Why the Correct Answer is Right**
The correct answer is related to the X-linked recessive trait of color vision deficiency caused by mutations in the OPN1LW gene, which codes for the long-wavelength cone opsin (L-cone). This gene is located on the X chromosome, and mutations in this gene lead to a deficiency in the perception of red light, not blue light. However, the person's condition is likely due to a defect in the S-cone, which is responsible for detecting short-wavelength blue light. This condition is known as blue cone monochromacy.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it refers to red-green color blindness, which is a different form of color vision deficiency caused by mutations in the OPN1MW gene.
* **Option B:** This option is incorrect because it refers to a condition where a person sees the world in shades of yellow and blue, not a defect in blue color appreciation.
* **Option C:** This option is incorrect because it refers to a condition where a person sees the world in shades of red and green, but not a defect in blue color appreciation.

**Clinical Pearl / High-Yield Fact**
Blue cone monochromacy is a rare form of color vision deficiency where a person sees the world in shades of blue and gray, but not red or green. This condition is often associated with other visual impairments, such as reduced visual acuity and increased sensitivity to light.

**Correct Answer: B. Tritanopia.**