Solve the Problem $n$ People, the Number of Possible Handshakes $N$ , Is Given By

Multiple Choice

Solve the problem.
-Within a group of $n$ people, the number of possible handshakes, $N$ , is given by $\mathrm{N}=\frac{1}{2}\left(\mathrm{n}^{2}-\mathrm{n}\right)$ . How many handshakes are possible at a meeting if 10 people are present?

A) 40
B) 90
C) 45
D) 55