How do you write 5 is to 1 as 20 is to 4 as a proportion in fractional notation?

A. 5/4 = 1/20

B. 5/1 = 4/20

C. 5/1 = 20/4

D. 5 : 1 :: 20 : 4

C. 5/1 = 20/4 is the correct proportion in fractional notation.