Help on math question?

Knowing the properties of the exponential function can help us decide on some properties that should be true of its inverse. Write e^a=l and e^b=m. Consider the property e^a*e^b=ea+b. Use this to show that f−1(lm)=f−1(l)+f−1(m) is a property of the inverse function.

In showing this one would apply the inverse function to the exponential property. Which of the following shows the result of this?
Choices:
A) f−1(l+m)=a⋅b
B) f−1(l⋅m)=a⋅b
C) f−1(l+m)=a+b
D) f−1(l⋅m)=a+b