Answer:
Option A
Explanation:
In co-dominance, two different traits associate with each other to produce an intermediate trait combining the characteristic of the two individual traits.
For example -
If red color flower is crossed with white color flower, then its co-dominated offspring would be oink in color.
Here -
Genotype of yellow dragon is YY
Genoype of yellow/Blue dragon is YB
YY * YB
YY, YB, YY, YB
Out of four off spring 2 are yellow and 2 are yellow/blue
So the ration of yellow and yellow/blue offspring are
2: 2
1: 1
Hence, option A is correct