Let f be an odd function defined on the set of real numbers such that for $\;x \geq 0\;$ ,$\;f(x)=3 sinx + 4 cos x$ .Then $\;f(x)\;$ at $\;x=-\large\frac{11 \pi}{6}\;$ is equal to :

Question

$(a)\;\large\frac{3}{2} + \normalsize 2 \sqrt{3}\qquad(b)\; -\large\frac{3}{2} + \normalsize 2 \sqrt{3}\qquad(c)\;\large\frac{3}{2} -\normalsize 2 \sqrt{3}\qquad(d)\;-\large\frac{3}{2} - \normalsize 2 \sqrt{3}$