To dilate means to make larger and when dilating a shape you make all sides go up by the same ratio not amount you don't just add the same number to each side. also I have to assume that the sides go in order for every answer. so to start you set up a ratio using the first side take the 16 from the instructions and put it over the first side in the first answer so 16/24 or 2/3 when reduced then take the second side from the instructions and first answer and set them up the same way 28/40 reduced to 7/10 now if these ratios were equal it would be the answer however because 7/10 doesn't equal 2/3 a is not the answer. do the same for all the answers and you will get c to be the answer