An investigation was carried out into the rate of photosynthesis under different environmental conditions. The graph shows the results. Which conditions could have produced the results for curve R?
- Apercentage carbon dioxide in air: 0.004; environmental temperature: 20^{\circ}C
- Bpercentage carbon dioxide in air: 0.04; environmental temperature: 30^{\circ}C
- Cpercentage carbon dioxide in air: 0.4; environmental temperature: 20^{\circ}C
- Dpercentage carbon dioxide in air: 4.0; environmental temperature: 30^{\circ}C