What are the broad areas that commercial refrigeration equipment is grouped in based on the ...

What are the broad areas that commercial refrigeration equipment is grouped in based on the evaporator coil temperature?
 
  A) Perishable frozen and perishable non-frozen
  B) Frosting, non-frosting, and defrosting
  C) Refrigerator and freezers
  D) High, medium, low, and cryogenic temperatures

 Q. 2

What is galvanic corrosion?
 
  A) Corrosion at the contact point of two types of metal in the presence of an electrolyte
  B) Corrosion due to chemical incompatibility between the coil and the refrigerant
  C) Corrosion due to oxidation and chemical attack
  D) Corrosion due to attack by metal eating organisms