How much protein does a $250 \ kg$ cow produce per day (in $g$)?

Single cell protein is an alternative protein source for animal and human nutrition formed from certain beneficial microorganisms like

Consider the following four statements $(A-D)$ and select the option which includes all the correct ones only.
$(A)$ Single cell $Spirulina$ can produce large quantities of food rich in protein,minerals,vitamins,etc.
$(B)$ Body weight-wise,the microorganism $Methylophilus$ $methylotrophus$ may be able to produce several times more proteins than the cows per day.
$(C)$ Common button mushrooms are a very rich source of vitamin $C$.
$(D)$ $A$ rice variety has been developed which is very rich in calcium.

Which of the following statements is incorrect regarding the use of Single Cell Protein $(SCP)$?

Which process is performed by microorganisms used in the production of Single Cell Proteins $(SCP)$?

Which type of microorganism produces $250$ grams of protein in a single day?