What is the difference between crushed ice and flake ice?

What is the difference between crushed ice and flake ice?
 
  A) Flake ice is made by spraying water into an evacuated chamber.
  B) Crushed ice is made as a cube and mechanically crushed.
  C) They are two names for the same product.
  D) Flake ice is made as a cube and shaved into flakes.

 Q. 2

Proper height above the roof is important when installing a heat pump rooftop unit
 
  A) to allow the condenser to take advantage of local prevailing wind
  B) so that the unit can be serviced from underneath
  C) to insure adequate combustion air to the burners
  D) so that snow does not block airflow through the outdoor coil

 Q. 3

Rooftop units can have the ductwork connected to either
 
  A) the bottom or top of the unit B) the top or side of the unit
  C) the bottom or side of the unit D) the main unit or a satellite blower coil