Assertion (A): Dumping of sewage into river water may decrease oxygen even below 4 mg/l.
Reason (R): Dumping of sewage pollutes river water heavily.
Identify the correct answer:
1
Both (A) and (R) are true with (R) being the correct explanation.
2
Both (A) and (R) are true, but (R) is not the correct explanation.
3
(A) is true, but (R) is wrong.
4
Both (A) and (R) are wrong.