When performing a water test be sure that:
1. all equipment is clean and in good working order
2. results are recorded carefully before making the test
3. test solutions, indicators, and reagents are fresh, and at full strength
4. test reagents are filtered before use
a) 1, 2
b) 2, 3
c) 1, 3
d) 2, 4
e) 3, 4
Answer: C