Help me plz I don't know how to this I don't understand!!!

The answer is B.

In order for this chart to be true, each x and y pair must be proportional to the other ones. (in other words, each row of x and y should increase the same amount as the other ones.)

look at the first row. we can write this as 3/5 (x over y). then look at the third and fourth row. 6/10 = 3/5, and 9/15 = 3/5, so the pairs are proportional.

its 4 because 2 times 2 is 4, if you double the number two you get four