The correct answer is indeed A. In an enumeration where you provide extra information about each item being enumerated, it is necessary to put a semi colon between each new item. So, in this case the writer wants to both enumerate the places the visitor went to and say which state each place belongs to. So, for giving the information about the state he/she used a comma, while for adding a new place he/she used a semi colon so as to make it clear that it is a new place being added to the list