witch pair of ratios form a proportion

Question

a= 4/15 and 16/65
b= 45/75 and 5/8
c= 63/36 and 7/4
d= 14/72 and 2/9

Answer 1

cross-multiply
4/15 ≠ 16/65 because 4*65 ≠ 15*16
now try the rest

Answer 2

Which ratios are equivalent to 30/80 ? (select all that apply)
A) 9/24

B) 8/3

C) 25/85

D) 180/480

E) 18/48