If $\; a \in R\;$ and the equation $\;-3(x-[x])^{2} + 2(x-[x]) + a^{2} =0\;$ (where [x] denotes the greatest integer $\; \leq x )\;$ has no integral solution , then all possible values of a lie in the interval :

Question

$(a)\;(-2 , -1)\qquad(b)\;(-\infty , -2) \cup (2 , \infty)\qquad(c)\;(-1 ,0) \cup (0,1)\qquad(d)\;(1,2)$