In horizontal microprogramming we need 1 bit for every control word, therefore total bits in
Now lets consider vertical microprogramming, In vertical microprogramming we use Decoder (n to 2n ) and output lines are equal to number of control words . A input is given according to what control word we have to select.
Now in this question these 5 groups contains mutually exclusive signals, i.e, they can be activated one at a time for a given group, we can safely use decoder.
group 1= ⌈ log220⌉=5 (Number of input bits for decoder, given output is number of control word in given group)
group 2= ⌈ log270⌉ =7
group 3= ⌈ log22 ⌉ =1
group 4= ⌈ log210⌉ =4
group 5= ⌈og223 ⌉=5
Total bits required in vertical microprogramming= 5+7+1+4+5=22
So number of control words saved= 125-22=103 hence (B) is answer