The perimeter of an isosceles triangle is 42 cm and its base is $$1\frac{1}{2}$$ times each of the equal sides. Find the length of each side of triangle:

A

12 cm, 12 cm, 18 cm

B

6 cm, 6 cm, 9 cm

C

18 cm, 18 cm, 24 cm

D

None of these