$$f ( x ) = \left\{ \begin{array} { c c } \frac { a x } { x + 2 b } \cdot \cot x & , x \neq 0 \\ 2 & , x = 0 \end{array} \right.$$
The function is continuous at the point $x = 0$.\\
Accordingly, what is the ratio $\frac { a } { b }$?\\
A) 1\\
B) 2\\
C) 4\\
D) $\frac { 1 } { 3 }$\\
E) $\frac { 1 } { 6 }$