The answer would be: c. High levels of dissolved oxygen
Oxygen is vital for most (aerobic) organism. Fish using oxygen that dissolved in the water so high level of dissolved oxygen will make the fish grow easier. Water with pH of 5 would be an acid water. Acid is corrosive and it can kill some organism that sensitive. High levels of fecal coliform mean the water contaminated with fecal material and must have a high level of bacteria.