The minister tried to assure the people regarding their safety.

Answer: Option A

Convince : cause (someone) to believe firmly in the truth of something.
Warn : inform someone in advance of a possible danger, problem, or other unpleasant situation.
Provide : make available for use; supply.
Protect : keep safe from harm or injury.
Assure : tell someone something positively to dispel any doubts.

Synonym of Assure is Convince