Use $\underset{x0}{lim}\frac{sinx}{x}=1$ and$/$or $\underset{x0}{lim}\frac{cosx-1}{x}=0$ to evaluate the following limit$.$

$\underset{x0}{lim}\frac{sin21x}{tanx}$

Select the correct choice and, if necessary, fill in the answer box to complete your choice.

A$.\underset{x0}{lim}\frac{sin21x}{tanx}=($Type an integer or a simplified fraction.$)$

B$.$ The limit is undefined.