A Primary Result for Stomatal Closure on a Hot, Dry

A primary result for stomatal closure on a hot, dry day would be

A) release of K⁺ ions to the apoplast and subsidiary cells.
B) displacement of Ca⁺⁺ ions from the thick inner walls of the guard cells.
C) disassembly of the microfibrils in the cell walls of the subsidiary cells.
D) upregulation of aquaporin synthesis.
E) downregulation of extension proteins.