People often fear cultures with whom they are unfamiliar with
The answer is B because "I have visited many cities including the following" indicates that there is going to be a list of cities. A colon is used to introduce a series of items or to separate two independent clauses; however the second sentence has to add on to the first.
You want to use ethos (ethics), logos (logic) and pathos (emotion) - use a lot of evidence, sound proof, emotions, be secure and selfconfident, you need to give people a reason to believe you.