In ROM, we don't compute anything, we just have to store the computed result. So just see how many address lines are needed to store all possible combination of result. here 4 bits need to multiply by 4 bits. so 8 address lines are
required to address 2^8=256 lines and in these lines, different value(result) will be stored in the form of
links. There are 8 data lines are required to receive the result because of max. value will be 1111 x 1111 =11100001.
Here 1st line will store the multiplication result of 0000 x 0000, and 256th line will store the result of 1111 x 1111 in the form of links between horizontal and vertical lines. Note that 0001 x 0000 & 0000 x 0001 will store the same result at 2 different places.