Answer is B
If each required at max 4 resources then by giving 3-3-3 resources each to 3 process and 1 remaining to anyone will simply make this system deadlock free.
If each process required min 2 resources than by giving 1 resource to each 9 processes and remaining 1 resource to any process will satisfy its need and system will be deadlock free.
Hence minimum processes = 3, maximum processes = 9
If you need formula then
MD = max demand -1 = 4-1 = 3
MN = min demand -1 = 2-1 =1
for min number of processes = ceil(Resources/MD) -1 = ceil (10/3) - 1 = 4-1 =3
for max number of processes = ceil (Resources/MN) -1 = ceil(10/1) -1 = 10-1 =9
