The circumference of circle b is 48. the circumference of circle a is 12. how many times greater is the area of circle b than the area of circle a? a. 4 times greater b. 8 times greater c. 16 times greater d. 48 times greater

We know that

area of circle b=[scale factor]²*area of circle a

scale factor=circumference of circle b/circumference of circle a
scale factor=48/12> 4
so
area of circle b=[4]²*area of circle a
area of circle b=[16]*area of circle a

therefore 
the answer is
c. 16 times greater