B, 2 is 1, which means this number must be odd.
The difference between c and 5 is 1, which means that the last digit of this number must be 4 or 9.
D. according to b and c, the last digit of this number must be 9.
E. from a and d, this number should be 63 times n=XXX9, and only 63 times a 3-digit number can get XXX9.
F, 63x3= 189, and the calculation shows that 189 is wrong.
G, 63x 13=8 19, and the calculation shows that 8 19 is wrong.
H, 63x23= 1449, correct.