In cows , when a pure-breeding (h) white cow is crossed with a pure-breeding (h) red cow , their off spring are spotted red and white. This is because the red and white alleles are Lethal
Recessive
Dominant
Codominant

Codominant

Explanation:

Often, when an individual has two different alleles that determine its certain trait, the effect of the dominant allele will be expressed, while the effect of the recessive allele will be hidden. For example, this is how we inherit eye color.

However, it isn't always like this. Sometimes, the effects of both (different) alleles are expressed. This phenomenon is called codominance, and the scenario you were given is an example of it.