The correct answer would be A. The first step in getting the gist would be to identify the keywords. Getting gist is the same as knowing the main idea of a certain passage. The very first to identify this should be to find keywords that you think is important in the text and speaks of the message of the passage.
D. "this was an uneasy secret..."
The answer in detail:
basically, the spelling is 'pizza' and you spell it, 'p i z z a'.
Photosynthesis produces oxygen and glucose mainly. The oxygen gets released into the air, because oxygen to plants is like carbon dioxide to us. It doesnt harm them, but they cant use it. The glucose ends up either being used by the plant or stored somewhere within the plant to be used later.