$\int \frac{d x}{x^{2}-9}=$ কত?

$\ln \left|\frac{x-3}{x+3}\right|+c$

$\ln \left|\frac{x+3}{x-3}\right|+c$

$\frac{1}{6} \ln \left|\frac{x-3}{x+3}\right|+c$

$\frac{1}{3} \ln \left|\frac{x+3}{x-3}\right|+c$