Single Cell Protein $(SCP)$ is obtained through which process?

What does Single Cell Protein $(SCP)$ help to reduce?

Consider the following four statements $(1-4)$ and select the option that includes all the correct statements:
$(1)$ The unicellular $Spirulina$ can produce large quantities of food rich in protein,minerals,vitamins,etc.
$(2)$ $Methylophilus$ $methylotrophus$,because of its high rate of biomass production and growth,can produce $25$ tonnes of protein per day.
$(3)$ Common button mushrooms are rich in Vitamin $C$.
$(4)$ Rice varieties have been developed which are rich in calcium.

Which of the following is an algal source of $SCP$?

Which microorganism produces 200 g of protein in a single day?

Torulopsis utilis is