Final answer:
A drop of mydriatic solution in the OD eye causes pupillary dilation.
Step-by-step explanation:
When a drop of mydriatic solution is placed in the right eye (OD), it causes pupillary dilation. Mydriatic solutions contain drugs that stimulate the sympathetic system and cause the radial fibers of the iris smooth muscle to contract. This contraction results in the pupil of the eye becoming larger.