The Owner of the St

The owner of the St.Paul Motor Inn in Minnesota is expanding the property and wants to install a new indoor swimming pool.To prevent heat loss, the owner plans to install the pool in as air-tight an enclosure as possible.As the facilities manager at the inn, you have been researching the swimming pools and pool heaters on the market.Based on what you've learned, you decide to recommend that the property should not purchase a directly fired heater for the new indoor pool, because directly fired water heaters:

A) cause algae overgrowth, which leads to severe maintenance problems.
B) cannot maintain a warm-enough pool temperature in your cold northern climate.
C) have been blamed for incidents of carbon monoxide poisoning when used for indoor pools.
D) are likely to provide uneven heating of the pool water, which would make swimmers uncomfortable.