Question

Which of these buildings is most likely to have indoor air pollution?

A. a school with leaks that allow water and heat to be wasted
B. an office building without carbon monoxide detector
C. a tightly sealed house with and unvented water heater

Answer 1

the correct on is c hope this helps 

Answer 2

The question is asking: Which of these buildings is most likely to have indoor air pollution? and we have two scenarios with a problem :
A. a school with leaks that allow water and heat to be wasted
and
C. a tightly sealed house with and unvented water heater". (B is a perfectly good scenario without any pollution. ) In A) the problem is a waste of resources, not pollution, and the answer is C- here, the pollution from the water heater would stay in the house.