The length of the diagonal of a square is \(j + 3\). Which of the following represents the area of the square?
(A)\(j^2 + 9\) (B)\(j^2 + 6j + 9\) (C)\((j^2 + 9) \sqrt { 2 } \) (D)\(\frac { j^2 + 9 } { 2 } \) (E)\(\frac { j^2 + 6j + 9 } { 2 } \)
E