C and D aren’t the answer,which leaves A and B. I’m guessing the answer is B.
( A ) IS THE ANSWER. IF MY ANSWER IS WRONG PLS FORGIVE ME
The mass of the object and its speed.
"Derm" = skin.
So, when you are going into this field to practice skin diseases and treatment, the word you're looking for is a <u><em>dermatologist. </em></u>
A dermatologist <em>is a special doctor that manages diseases within the skin, hair, and nails. </em>