During glacial periods in the early evolution of land plants,which of the following would have been a beneficial adaptation regarding the number of stomata per unit surface area,and what accounts for it?

A)increased numbers of stomata, to maximize absorption of increasing levels of atmospheric CO₂
B)increased numbers of stomata, to maximize ability to absorb low levels of atmospheric CO₂
C)decreased numbers of stomata, to retain CO₂ produced by the chloroplasts
D)decreased numbers of stomata, to maximize absorption of low levels of atmospheric CO₂