Which algae is rich in protein?

Give information about $SCP$.

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.

Explain single cell protein $(SCP)$.

Blue-green algae like $Spirulina$ can be grown on which of the following?

Methylophilus methylotrophus is which type of organism?