Answer:
c
Explanation:
a: 9/5 and 19/10 are already in simplest form
b:25/35 can be simplified to 5/7 if you divide each side by 5 and 20/24 can
be simplified to 5/6 if you divide each side by 4
c: both 15/10 and 21/14 can be simplified to 3/2
d: 4/6=2/3 and 10/16=5/8