He has had this lesion since their wedding 35 years ago but lately it became darker and irregular

A 62-year-old farmer visits his physician at his wife’s request who noticed that he had an irregular dark pigmented lesion on his back. According to his wife, he has had this lesion since their wedding 35 years ago but lately it became darker and irregular.
What is the most important prognostic factor in this case?
A-Age of the patient
B-Color of the lesion
C-Depth of the lesion
D-Diameter of the lesion
Answer: http://bit.ly/2OOI3qx

ANs B