A normal-visioned man whose father was colour blind, marries a woman whose father was also colour blind. They have their first child as a daughter. What are the chances that this child would be colour blind?

The correct option is B 0%
There are 0% chances that the girl is color blind. She can be a carrier of the genetic disorder but can't be affected by it because it is an X-linked disorder.

So, the correct answer is 0%.