In sewage treatment, the detention period allowed for oxidation ponds ranges from __________ weeks.

Question: In sewage treatment, the detention period allowed for oxidation ponds ranges from __________ weeks.
[A].

1 to 2

[B].

4 to 5

[C].

9 to 10

[D].

15 to 20

Answer: Option B

Explanation:

No answer description available for this question.