Which sentence would be most effective if inserted at the beginning of paragraph D?

— ExhibitC

— Exhibit -

Which sentence would be most effective if inserted at the beginning of paragraph D?
A . Watering is always an issue.
B . A lot of people collect rain water to water their gardens.
C . As a result of dams, many rivers have been turned into massive lakes, providing water and recreation to numerous towns and cities.
D . Water is regarded either as hard or soft depending on the mineral deposits found in the water.
E . Water is a combination of two elements―oxygen and hydrogen.

Answer: A