The length of a rectangle is 5.4 cm more than 2 times the width. If the perimeter of the rectangle is 39.6 cm, what are its dimensions?
a. length = 4.8 cm; width = 15 cm
b. length = 15 cm; width = 4.8 cm
c. length = 15 cm; width = 10.2 cm
d. length = 4.2 cm; width = 10.2 cm