They want to have another are the chances of that child being a carrier?

Healthy parents have 2 children, a child with Cystic fibrosis and a healthy child.

They want to have another are the chances of that child being a carrier?
A . 1:2
B . 1:4
C . 1:8
D . 1:16
E . 2:3

Answer: A

Explanation:

As the parents have a child with cystic fibrosis and they are healthy both of them are carrier. autosomal recessive disease where if both parents are carrier mode of inheritance is as follows: Chance of being child 1:4, Chance of being diseased 1:4 and chance of being carrier 1:2.