Composite resistance = 50 ohm
Current = 4 A
Each resistance = 100 ohm
Each resistance carry a current = 1 A
In one pair, two resistance connected in series.
So, the value of one pair of resistance is 200 ohm because each resistance is 100 ohm.
Now, four pairs of resistance connected in parallel
We need to calculate the equivalent resistance
Using the formula of parallel
1/Req = 1/200+1/200+1/200+1/200
1/Req = 1/50
Req = 50Ω
Hence, The minimum number of resistance to be used is 8.
(B) is the correct option.