Which of the following is used in the production of curd,butter,cheese,sweets,etc.?

$A$ released by $LAB$ during growth coagulate and partially digest $B$. Here $A$ and $B$ refer to:

Which of the following are the main benefits of $LAB$?
$I.$ Increase vitamin-$B_{12}$ amount,thus increasing nutrient quality of milk.
$II.$ Checks disease-causing microbes in the stomach.
Choose the correct option.

Study the following flow chart that shows curd formation from milk and select the correct option for $A$ and $B$.
Milk is incubated with curd
$\downarrow$
$LAB$ shows growth in milk
$\downarrow$
Production of .....$A$.....
$\downarrow$
Coagulation and digestion of milk protein
$\downarrow$
Improved nutritional quality by increased ....$B$....

$P$ - Statement: Humans consume milk as a food item.
$Q$ - Statement: Milk is used to produce curd,butter,cheese,sweets,etc.

Statement $P$: Baker's yeast is used to make bread.
Statement $Q$: $LAB$ (Lactic Acid Bacteria) increases the quality of vitamin $B_{12}$.