Question

How do Curves A and B compare to each other with respect to f and f ′?
The answer cannot be determined.
f: Curve B, f ′: Curve A
f: Curve A, f ′: Curve B
Neither Curve A nor Curve B are derivatives of each other.

Answer 1

It's likely that curve A is f and curve B is f '.

The points where curve B crosses the horizontal axis correspond to the extrema of curve A at around 0 and 0.45, and the extremum of curve B corresponds to the inflection point of curve A at around 0.2. These observations are consistent with the first and second derivative tests.