If atmospheric CO₂ concentrations increase twofold or more,how will plants be affected,disregarding any changes in climate?

A)All plants will experience increased rates of photosynthesis.
B)C₃ plants will have faster growth; C₄ plants will be minimally affected.
C)C₄ plants will have faster growth; C₃ plants will be minimally affected.
D)C₃ plants will have faster growth; C₄ plants will have slower growth.
E)Plant growth will not be affected because atmospheric CO₂ concentrations are never limiting for plant growth.