Solve the Problem $c ( n ) = \frac { 1 } { 2 } \left( n ^ { 2 } - n \right)$

Multiple Choice

Solve the problem.
-The number of different committees of 2 students where the 2 students are selected from a group of n students is given by $c ( n ) = \frac { 1 } { 2 } \left( n ^ { 2 } - n \right)$ n) . How many different committees of 2 students can be selected from a group of 10
Students?

A) 10
B) 20
C) 45
D) 1