Consider the following statements.A. Avoid building up of sewer gasesB. Ensure atmospheric pressure in the wastewater surfaceC. Ensure the safety of sewer maintenance peopleD. Provide oxidation facility to sewageWhich of these statements correctly suggest why ventilation of sewer lines is necessary?

Consider the following statements.A. Avoid building up of sewer gasesB

1.	Consider the following statements.A. Avoid building up of sewer gasesB. Ensure atmospheric pressure in the wastewater surfaceC. Ensure the safety of sewer maintenance peopleD. Provide oxidation facility to sewageWhich of these statements correctly suggest why ventilation of sewer lines is necessary?
A.	Only A, B and C
B.	Only A, C and D
C.	Only B, C and D
D.	Only A, B and D
Answer» B. Only A, C and D