What inference can be made about the availability of food, based on this passage? there was plenty of food in elizabethan england. there was never enough food in elizabethan england. the winter months produced less food. the summer months produced less food?

The answer is: the winter months produced less food. 

The word "storage of food is most important" that start the passage telling that storing food in ideal condition is important.
The word "a valuable source of protein in the long winter season" signifies the need to keep the food in a long time. The reason why you need to store food for the winter season is that the land produces less food than demand, so you need to supply it from storage