challenge: Which of the following defines a microlift glider as a sub-type of the ultralight class?
  
  A. Maximum altitude not exceeding 10,000 feet
  B. Wing loading not exceeding 18 kg/m2 (3.69 lb/ft2)
  C. Take-off mass not exceeding 220 kg (486 lb)
  D. Wing span not exceeding 20 meters
  Answer: 