If $u=3x^{12}$ and $v=x^6$, then $\frac{du}{dv}$ is:

$6x^6$ $36x^{11}$ $6x^5$ $3x^6$

$6x^6$

$u=3x^{12},\,v=x^6⇒u=3v^2⇒\frac{du}{dv}=6v=6x^6$