Will someone help me plz

The level of co2 emissions, f(x), in metric tons, from the town of fairfax x years after they started recording is shown in the table below. x 2 4 6 8 10 f(x) 26,460 29,172.15 32,162.29 35,458.93 39,093.47 select the true statement.

Table which ratio is equivalent to 3: 7? 6: 7 3: 21 24: 56 15: 30

Having a hard time understanding this question (see attachment).