Concept:Oral Rehydration Therapy:Rehydration by mouth In oral rehydration therapy, salt is a solution of glucose-based salt solution.WHO and UNICEF propose a single glucose-based ORS formulation to treat or prevent dehydration in people of all ages who have diarrhoea from any cause, including cholera.Unlike other fluids, the chemicals in an ORS are proportioned to what the body requires to recover from diarrhoea.Explanation:A combination of sugar and salt can be easily absorbed:The intestines absorb fluids more efficiently when sugar and salt are consumed with water.This solution rehydrates the body more effectively than water alone after a bout of diarrhoea. Boiling water makes the water germ-free:The most effective way to kill disease-causing organisms including viruses, bacteria, and parasites is to boil the water.Some bacteria are dangerous to consume and can cause digestive issues, as well as cramping and diarrhoea symptoms.When a person does not have access to safe, treated water, boiling water is the most effective way of purification.When water exceeds 2120 Fahrenheit, many species cannot survive.Thus,(A) only sugar water cannot be absorbed into the intestine- Incorrect.(B) Combination of sugar and salt can be easily absorbed- Correct.(C) boiling water makes the water germ-free- Correct.So, the correct options are B and C only.