GRE Question of the Day (September 12th)

If \({a}\), \({b}\), \({c}\) and \({d}\) are four consecutive integers (not necessarily in that order), and \({a^b = c^d}\), what is the [u]least[/u] possible value of \({a+b+c+d}\) ?

A) -8
B) -6
C) -2
D) 6
E) 12