Answer:
By an online search, i found that the options are:
Option A. A(10)
Option B. A(11)-A(9)
Option C. A(10)/10
Option D. A’(10)
Let´s start by defining the concept of a derivative.
When we have a function f(x), the derivative, f´(x), is a measure of the rate of change of f(x) with respect to the variable x.
Then if A(t) represents the area covered by the oil, A´(t) is the rate of change of this area as a function of t.
Particularly, A´(10), will be the rate of change at t = 10.
Then the correct option is: Option D. A´(10)
