Find the parametric equations and symmetric equations for the line of intersection of the given planes: x + y + z = 7 and x + z = 0. Which of the following is the correct set of equations?

A) x = t, y = -t + 7, z = -t
B) x = t, y = t + 7, z = -t
C) x = t, y = -t + 7, z = t
D) x = t, y = t + 7, z = t