why is the DFS of a delta function equal to 1
$X[k]= \sum_{n=0}^{N-1} \delta[n]W_N^{kn} \quad$, where $\&gt;W_N^{kn}=e^{−j\,2\pi k\,n/N}$

HINT:

What is the value of $\delta[n]$ when $n \neq 0 \&gt;$ ?