Processes directly affecting Photosynthesis

I need the answer to Number two but it requires the answer to Number one which the professor definitely said it was E.

1.) Rates of Photosynthesis in C3 plants can be approximated by measuring:
         a.) CO2 released minus O2 consumed by a leaf in the light
         b.) The total amount of O2 and CO2 released from a leaf in the light
         c.) The total amount of CO2 and O2 consumed from a leaf in the light
         d.) CO2 consumed by a leaf in the dark
         E.) O2 released by a leaf in the light

2.) Based on your answer to Number 1, which of the following processes would DIRECTLY affect the accuracy of your measurements of photosynthesis?
         a.) Carbon Dioxide fixed by RUBISCO
         b.) Oxygen being reduced to form water in mitochondria
         c.) Carbon Dioxide release due to glycolysis and the citric acid cycle
         d.) All of the Above
         e.) Only a and b above



Thank you!!