Which of the following is a measure for the control of bilharzia?

Schistosomiasis, also known as bilharzia or 'snail fever', is a disease caused by parasites (worms called schistosomes) carried by freshwater snails.

Schistosomiasis control focuses on reducing disease through periodic, large-scale population treatment with medication;

a more comprehensive approach including potable water, adequate sanitation, and snail control would also reduce transmission.