Question 2
On what basis is autotrophic nutrition divided into photoautotrophic and chemoautotrophic?
The right answer is the one marked above.
The energy used to produce the food. Sunlight makes it photoautotrophic; a chemical reaction makes it chemoautotrophic.
In both cases the food produced is organic material, so the material the food is made from is no basis for a division. Where the food is stored, and the size of the organism, are irrelevant here.