The concentration of dissolved Oxygen in water for growth of fish should be more than X ppm and Biochemical Oxygen Demand in clean water should be less than Y ppm. X and Y in ppm are, respectively.

We need to identify the minimum dissolved oxygen (DO) for fish growth and the BOD limit for clean water.

For the healthy growth of fish, the concentration of dissolved oxygen in water should be more than 6 ppm. Below this level, fish survival becomes difficult.

Clean water has a Biochemical Oxygen Demand (BOD) of less than 5 ppm. Water with BOD above 5 ppm is considered polluted, and highly polluted water has BOD > 17 ppm.

$$X = 6$$ ppm (dissolved oxygen for fish) and $$Y = 5$$ ppm (BOD for clean water).

The correct answer is Option A: X = 6, Y = 5.