Find the Relative Maximum and Minimum Points of the Function $f(x)=x^{3}-x^{2}+15 x+8$

Multiple Choice

Find the relative maximum and minimum points of the function $f(x) =x^{3}-x^{2}+15 x+8$ .

A) Relative maximum at $(1,15)$ ; relative minimum at $(5,-17)$ .
B) Relative maximum at (7, 15) ; relative minimum at ( $-1,-17$ ) .
C) Relative maximum at $(8,64)$ ; relative minimum at $(-2,-66)$ .
D) Relative maximum at $(5,15)$ ; relative minimum at $(1,-17)$ .