The correct option is A of
In the given sentence the speaker explains about the places he/she visited during the trip. The ‘number’ here consists of a list that is created using the various places visited. The preposition ‘of’ is used to highlight belonging and connection, which is apt for the given context since it connects the ‘number’ and the list of ‘places’. Hence option A is correct. On the other hand, we shouldn’t use ‘with’ because ‘with’ denotes either the company of people or the use of something i.e. inanimate object or tool to perform an action. Thus option B is incorrect because the speaker is not visiting a ‘number’ using a list of places. Similarly, when we use prepositions ‘at’ and ‘in’ the meaning of the sentence changes. It would mean that ‘number’ is a person that the speaker visits ‘at’ or ‘in’ a few places. Thus options C and D are incorrect.