Which of the following facilities opening of stomatal aperture?

When the turgidity increases within the two guard cells, the thin outer walls bulge out and stomata opens. The microfibrils in guard cells are made up of cellulose oriented radially rather than longitudinally making it easier for the stomata to open. Thus, the correct answer is option A (Radial orientation of cellulose microfibrils in the cell wall of guard cells).