Cholera, typhoid, diphtheria and tuberculosis cause huge numbers of deaths. Drinking water has always been the worlds greatest single vector of sickness. Disease is transmitted when sewage and drinking water come into contact. Children are particularly vulnerable. In the 19th century half of all children died before the age of 5. In some of the poorest countries the infant mortality rate still stands as high as one in eight. This compares with a rate of 1 in 100 in countries where drinking water is safe. The separation of sewage and the supply of clean drinking water are the domain of civil engineers, and their work makes a significant contribution to public health. That contri- bution was at last recognized when public sanitation was voted the greatest medical breakthrough, beating discoveries including antibiotics, vaccines and anaesthesia in a poll organized by the British Medical Journal.

Question: The first two sentences are sufficient to draw the conclusion that water-borne disease is still the greatest transmitter of sickness.
Options:
A. true, B. false, C. uncertain
Answer: "B"