Choose the correct order of steps for the synthesis of vitamin d.

a. inactive vitamin d is transported to the liver where it is modified.
b. inactive, chemically altered vitamin d is transported to the kidneys.
c. uv light strikes the skin and converts a steroid molecule into an inactive form of vitamin d.
d. vitamin d is activated under the influence of pth.

a. d, a, c, b
b. a, c,b, d
c. a, b, c, d
d. c, a, b, d
e. c, b, a, d