Ans.
The phenotype is defined as physical characteristics or physical expression of that trait. These characters are influenced by genes and environmental conditions. As arctic foxes and other arctic animals show white coat, due to non-functional pigment-producing genes during winters, there is a change in their phenotypic characters (physical appearance).
This show a phenotypic change due to environmental influence as it helps them to adapt in cold environment. Thus, the correct answer is option D). 'phenotypic.'