A,C, and E are all together … Another set is D and B You could use 4 and 7 as the base 4*4=16 7*4=28 4*5=20 7*5=35 ————————————————— 2 and 3 are the base in the next set; 2*4=8 3*5=15 ————————————————— Sorry if it’s confusing but I believe that’s the answer