in home insured under an $HO3.$ Tired of Wisconsin's $1.$ Bill and Carol Snowbird own a Wiscons winter in Texas. Under which one of the following long winters, they decided to spend this w be covered by their $HO3?$ circumstances would

a$.$ Before the Snowbirds left for Texas, Bill completely shut off the home's water supply. While they were gone, their home was destroyed by a fire that would have caused only limited damage if the water supply to their sprinkler system had been maintained.

b$.$ Before the Snowbirds left for Texas, Carol realized they could save money by turning off the furnace. She never thought of also shutting off the water, and the house sustained water damage when frozen pipes burst and then thawed.

c$.$ Before the Snowbirds left for Texas, they had their furnace inspected, filled the fuel oil tank, and set their thermostat at $60$ degrees. However, their furnace malfunctioned and caused water pipes to burst.

d$.$ Before the Snowbirds left for Texas, they set their thermostat at $70$ degrees. However, the furnace stopped running when their supply of fuel oil ran out, causing water pipes to burst.