after visiting a wastewater treatment plant, Shelly has a few questions. Which question can be answered through scientific investigation?
a:how much Wastewater is treated per day in the wastewater treatment plant?

b:are employees at the wastewater treatment plant satisfied with their jobs?

c: are the investors unhappy with the revenue generated by the wastewater treatment plant?

d:what should be the role of the government in promoting the wastewater treatment plant?​