What Was the Primary Reason Why Improvements in Sanitation and Water

What was the primary reason why improvements in sanitation and water purification systems were made during the Industrial Revolution?

A) Medical scientists discovered bacteria during this time and linked them to various diseases.
B) Medical scientists thought that cleanliness would strengthen the moral constitution of individual patients.
C) Medical scientists increased treatments such as the bleeding of the sick that required the use of water.
D) Medical scientists argued that improved water supplies were necessary to help increase crop yields.
E) Medical scientists observed that cholera outbreaks were concentrated in urban areas with poor sanitation.