Read the following four statements 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. Golden rice variety has been developed which is very rich in calcium.