Solve
-The Equation $D = \frac { 1 } { 2 } \mathrm { n } ( \mathrm { n } - 3 )$

Multiple Choice

Solve.
-The equation $D = \frac { 1 } { 2 } \mathrm { n } ( \mathrm { n } - 3 )$ gives the number of diagonals $\mathrm { D }$ for a polygon with $\mathrm { n }$ sides. Find the number of diagonals for a polygon that has 7 sides.

A) 4 diagonals
B) 28 diagonals
C) 35 diagonals
D) 14 diagonals