Evaluate the integral ${\displaystyle \underset{0}{\overset{7}{}}}\sqrt[\phantom{2}]{x^{2}49}dx$

$\frac{7\sqrt[\phantom{2}]{2}}{2}\frac{7}{2}ln(1\sqrt[\phantom{2}]{2})\frac{7}{9}$

$\frac{7\sqrt[\phantom{2}]{2}}{3}\frac{7}{2}ln(1\sqrt[\phantom{2}]{3})$

$\frac{49\sqrt[\phantom{2}]{2}}{2}\frac{49}{2}ln(1\sqrt[\phantom{2}]{2})$

$\frac{49\sqrt[\phantom{2}]{2}}{2}-\frac{49}{2}ln(2\sqrt[\phantom{2}]{2})$

$\frac{49\sqrt[\phantom{2}]{2}}{2}\frac{7}{2}ln(1\sqrt[\phantom{2}]{2})$