If black and white true-breeding mice are mated and the result is all gray offspring, what inheritance pattern would this be indicative of?
dominance
codominance
multiple alleles
incomplete dominance

Option B, Co-dominance

Explanation:

This is an example of codominance inheritance pattern.

When two alleles representing two different characteristic traits are expressed equally in the offsprings resulting from a cross, then this genetic inheritance pattern is called as codominance .

For example -

A red flower with genotype "RR" is crossed with a white flower "rr" resulting into pink color offsrping with genotype "Rr"

Here, both the red and white traits of flower color are expressed equally thereby giving pink color to the offspring flower.

The same thing is happening in case of true breeding black and white mice.

Hence, option B is correct