The growth regulator associated with drought stress tolerance is ........

The correct option is D Abscisic acid
During drought plants produce a hormone known as abscisic acid(ABA). It is called as stress hormone. The phytohormone abscisic acid plays a regulatory role in many physiological processes in plants. Different stress conditions such as water, drought, cold, light and temperature result in increased amounts of ABA. The action of ABA involves modification of gene expression and analysis of responsive promoters revealed several potential cis- and trans-acting regulatory elements.