Which of the statements are correct about bioreactors?
$I.$ It provides all the optimal conditions for achieving the desired product by providing optimal growth conditions like temperature, $pH$, substrate, salt, vitamin and oxygen.
$II.$ It is suited for large-scale production of microorganisms under aseptic conditions for a number of days.

• A
  $Only \; I$
• B
  $Only \; II$
• C
  $I \; and \; II$
• D
  $None \; of \; the \; above$