If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is__________.

A)
100 mg/l
B)
200 mg/l
C)
300 mg/l
D)
400 mg/l

Correct Answer :   400 mg/l