Write the scalar equation of the plane with normal vector ñ = [3, 2, 1] and passing through the point (4, 5, 6).
a) 3x+2y+z-28=0
b) 4x+5y+6z+28=0
c) 3x+2y+z+ 28 = 0
d) 4x+5y+6z-28 = 0