Respuesta :

The correct choice from given option is "B", "Lactobacillus"
It seems proper to explain a bit about the types of cells here. 
Two type of cells are: 
1) Prokaryotic: these cells have no nucleus and they are small and simple.
2) Eukaryotic: These cells have a nucleus and are large and complex as opposed to prokaryotic.

"Lactobacillus" belong to first stated category here.

Answer: B lactobacillus

Explanation:

it is a germ which helps in the soring of milk