The correct option is (C): 15
Explanation: The number of handshakes can be calculated using the formula \(\frac{n(n-1)}{2} = H\), where n is the number of persons and H is the total number of handshakes. Here, H=105.
So, setting up the equation:
\(\frac{n(n-1)}{2}\) = 105 \(\implies n(n-1) = 210\)
Testing n=15:
\(15(15-1) = 15 \times 14 = 210\)
Thus, there were 15 persons at the party.