The correct option is: (b) Von Mayer
Explanation:
Classical experiment for proving essentiality of CO2 for photosynthesis is Von Moll'* half leaf experiment. In this experiment one half of destarched leaf is inserted in air tight wide mouthed bottle having small quantity of KOH (for absorption of CO2) and illuminated. Starch test after one hour indicates absence in inserted half and presence in outer half (where CO2 is available).
