적분 $\displaystyle \int _ {0} ^ {1} {\ln} \left (x+ \sqrt {x^ {2} +1} \right) d x$ 를 구하면?

• ①$1- \sqrt {2} + {\ln} (1+ \sqrt {2})$
• ②$1+ \sqrt {2} + {\ln} (1+ \sqrt {2})$
• ③$3- \sqrt {2} + {\ln} (3+ \sqrt {2})$
• ④$3+ \sqrt {2} + {\ln} (3+ \sqrt {2})$
• ⑤$1+ \sqrt {2} + {\ln} (3+ \sqrt {2})$