Choose the incorrect statement regarding the human digestive system with reference to a normal person.

• A
  Human saliva is slightly acidic.
• B
  In human beings,four pairs of salivary glands secrete saliva.
• C
  The quantity of saliva in an adult man may be $1$ to $1.5 \; L$ per day.
• D
  Enzyme amylase present in saliva is responsible for the breakdown of starch into simple sugar.