Answer
$2$ solutions if $4\gt c$, one solution is $4=c$, no solution if $4\lt x$.
Work Step by Step
The discriminant is $D=b^2-4ac$. If $D\gt0$ we have $2$, if $D=0$ we have one, and if $D\lt0$, we have no solution.
Hence here $D=16-4c$. $16-4c\gt0\\16\gt4c\\4\gt c.$
$16-4c=0\\16=4c\\4= c.$
$16-4c\lt0\\16\lt4c\\4\lt c.$
Thus we have $2$ solutions if $4\gt c$, one solution if $4=c$, and no solution if $4\lt x$.
