Answer:
C. 4/5
Explanation:
I am going off the beleif that you meant 0.5 instead of 5.
2/4 = 0.5
3/6 = 0.5
4/5 = 0.8
10/20 = 0.5
The only thing that doesnt equal 0.5 is C. 4/5
You can also think about the numerator (top number) x 2 to equal the denominator (bottom number).
Hope this helps! :)