for first fit:
3 will be placed in paritition of size 5, 2 in 10 and 12 in 30
so total fragmentation=(5-3)+(10-2)+(30-12)=28
for best fit:
3 will be placed in paritition of size 5, 2 in 2 and 12 in 30
so total fragmentation=(5-3)+(12-2)+(30-12)=20
so best fit is better
ans is c