Which of the following is a rational number?\\ A) $\sqrt { 2 } + 1$\\ B) $2 \sqrt { 2 } - 1$\\ C) $\frac { 1 } { \sqrt { 2 } }$\\ D) $\frac { \sqrt { 2 } } { \sqrt { 2 } + 1 }$\\ E) $\frac { 2 \sqrt { 2 } - 2 } { 3 \sqrt { 2 } - 3 }$