Which of these is the result of completing the square for the expression $x^2+8 x-30$ ?
A$(x+4)^2-30$
B$(x+4)^2-46$
C$(x+8)^2-30$
D$(x+8)^2-94$
A$(x+4)^2-30$
B$(x+4)^2-46$
C$(x+8)^2-30$
D$(x+8)^2-94$