How many of the following statements are correct regarding the process of converting milk into curd?
$I -$ The bacteria responsible for this process are $LAB$.
$II -$ $LAB$ produces acids that coagulate the milk.
$III -$ The protein present in milk is partially digested.
$IV -$ It increases the nutritional quality by increasing the amount of Vitamin $B_{12}$.

• A
  $3$
• B
  $4$
• C
  $1$
• D
  $2$