Use a Graphing Calculator to Find the Coordinates of the Turning

Multiple Choice

Use a graphing calculator to find the coordinates of the turning points of the graph of the polynomial function in the indicated domain interval. Give answers to the nearest hundredth.
- $$f ( x ) = - x ^ { 3 } - 8 x ^ { 2 } + 21 x + 108 ; [ 1,2 ]$$

A) $( - 3.50 , - 106.37 )$
B) $( 0 , - 12 )$
C) $( 1.09,120.09 )$
D) $( - 6.42 , - 621.94 )$