$k$ Is a Real Number $n$ Is a Positive Integer, And

Multiple Choice

$\text { Evaluate } \left( \begin{array} { l } 7 \\5\end{array} \right) \text { using the formula } \left( \begin{array} { l } k \\n\end{array} \right) = \frac { k ( k - 1 ) ( k - 2 ) ( k - 3 ) \cdots \cdots ( k - n + 1 ) } { n ! } \text { where }$
$k$ is a real number, $n$ is a positive integer, and $\left( \begin{array} { l } k \\ 0 \end{array} \right) = 1$

A) 31
B) 45
C) 56
D) 21
E) 35