单项选择题
Questions 11-15 are based on the following passage:
Firefighters are often asked to speak to school and community groups about the impertance of fire safety,particularly fire preveton and detection.Because smoke detectors reduce the risk of dying in a fire by half,firfighers often provide audiences with information on how to install these protective devices in their homes.
Specifically,they tell them these thing:A smoke detector should be placed on each floor of a home.While sleeping,people are in particular danger of an emergent fire,and there must be a detector outside each sleeping area.A good site for a detector would he a hallway that runs between living speces and bedrooms.
Because of the dead-air space that might be missed by hot air bouncing around above a fire,smoke detectors should be installed either on the ceiling at least four inched from the nearest wall,or high on a wall at least four,but no further than twelve,inches from the ceiling.
Detectors should not be mounted near widnows,entrances,or other places where dirafts（过堂风）might direct the smoke away from the unit.Nor should they be palced in kitchens and garages,where cooking and gas fumes are likely to cause false alarms.
A.on any level of a home
B.outside all bedrooms in a home
C.in all hallways of a home
D.in kitchens where fires are most likely to start