Consider the following four statements (i-iv) and select the option which includes all the correct ones only.

i. Single cell Spirulina can produce large quantities of food rich in protein, minerals, vitamins, etc.

ii. Body weight-wise, the micro-organism Methylophilus methylotrophus may be able to produce several times more proteins than the cows per day.

iii. Common button mushrooms are a very rich source of vitamin C.

iv. A rice variety has been developed which is very rich in calcium.