If the sum of \(a\) and \(b\) is \(c\), what is the average (arithmetic mean) of \(a\), \(b\), and \(c\)?
(A)\(2c\) (B)\(\frac { 2c } { 3 } \) (C)\(\frac { a + b } { c } \) (D)\(\frac { 3c } { a + b } \) (E)\(c - (a + b)\)
B