Respuesta :

i would say D my dear friend from what i see from the patterns hope it helps :) and sorry if its wrong i tried lol
C Because the Ratio is 6:10 or 12:20 or 18:30 or 24:40 or 30:50

In this example you double both sides of the ratio, 
and then you keep doing it until you find the right ratio that works as an answer choice.

Tell me if i dont make any sense.