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

The alga rich in protein is

One of the alternative sources of protein for human and animal nutrition is ........ .

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.

How much protein can a methylotroph like Methylophilus methylotrophus produce in a single day?

Which organism's filaments are used in the production of Single Cell Protein $(SCP)$?