If $f(x)=[x^2]-[x]^2$ where [.] is the largest integer function then

Question

$\begin{array}{1 1}(a)\;\text{f(x) is discontinuous for all integral value of x}\\(b)\;\text{f(x) is discontinuous only at x=0,1}\\(c)\;\text{f(x) is continuous only at x=1}\\(d)\;\text{None of these}\end{array}$