Drinking water is regularly tested to ensure that it is safe for consumption - HSC - SSCE Chemistry - Question 6 - 2060 - Paper 1

To determine the highest drinking water quality, we need to analyze the parameters given in the table: dissolved oxygen, nitrates, total dissolved solids, and turbidity.

1. Dissolved Oxygen (DO): Higher levels of dissolved oxygen are favorable as they indicate better water quality. Here, options B and D have the highest DO values (8 mg/L).

2. Nitrate Levels: Lower nitrate levels are preferable as high concentrations can indicate pollution. Options A and B have lower nitrate levels (0.1 mg/L) compared to C and D (2 mg/L).

3. Total Dissolved Solids (TDS): Lower TDS values are generally indicative of better water quality. Options A and B have a TDS of 50 mg/L which is preferable compared to C (200 mg/L) and D (200 mg/L).

4. Turbidity: Low turbidity (measured in NTU) signifies clearer water and is thus preferable. Option B has the lowest turbidity value (2 NTU) compared to A (50 NTU), C (2 NTU), and D (50 NTU).

After evaluating all key parameters, Option B (Dissolved Oxygen: 8 mg/L, Nitrate: 0.1 mg/L, Total Dissolved Solids: 50 mg/L, Turbidity: 2 NTU) represents the highest drinking-water quality.