If the line $3 x+4 y+20=0$ touches the circle $x^{2}+y^{2}=16$, then the point of contact is
(a) $\left(\frac{-12}{5}, \frac{-16}{5}\right)$
(b) $\left(\frac{12}{5}, \frac{16}{5}\right)$
(c) $\left(0, \frac{-16}{5}\right)$
(d) $\left(\frac{12}{5}, 0\right)$