The notice said that the meeting would begin precisely at 9.30 AM.

Answer: Option B

approximately : used to show that something is almost, but not completely, accurate or exact; roughly.
exactly : used to emphasize the accuracy of a figure or description.
inaccurately : in an incorrect or inexact manner.
concisely : in a way that is brief but comprehensive.
precisely : in exact terms; without vagueness.

Synonym of precisely is exactly