Find the absolute extrema of the function, if they exist, over the indicated interval. Also indicate the x-value at which each extremum occurs. If no interval is specified, use the realnumbers, (−∞,∞).

f(x)=-x^3+2x^2+4x-7; (0,∞)

Select the correct choice below and, if necessary, fill in the answer boxes to complete your choice.

A. The absolute maximum is nothing at x equals=nothing and the absolute minimum is nothing at x equals=nothing.

B. The absolute minimum is nothing at x equals=nothing and there is no absolute maximum.

C. The absolute maximum is nothing at x equals=nothing and there is no absolute minimum.

D. There is no absolute maximum and no absolute minimum