${\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{\sqrt[\phantom{2}]{t^2-49}}{t}dt=$

Select one:

$a.$

$\sqrt[\phantom{2}]{t^2-49}-7se{c}^{-1}(\frac{t}{7})+C$

$b.$

$\frac{\sqrt[\phantom{2}]{t^2-49}}{7}-se{c}^{-1}(\frac{t}{7})+C$

$c.$

$\sqrt[\phantom{2}]{t^2-49}-\frac{1}{7}se{c}^{-1}(\frac{t}{7})+C$

$d.$ None $of$ them

$\frac{1}{\sqrt[\phantom{2}]{t^2-49}}-7se{c}^{-1}(\frac{t}{7})+C$