Write a rule for the function whose graph can be obtained from the given parent function by performing the given transformations.
parent function: f(x) = [x]
transformations: shift the graph 6 units to the right, stretch it vertically by a factor of 2, and shift it downward 3 units.
a. g(x) = 2[x - 6] - 3
C. g(x) = 2x - 18
b. g(x) = 6(x2 – 3)
d. g(x) = -3(x - 2) + 6