这是主谓一致的问题：
主语后面跟由with,together with,along with,like,in addition to,as well as,rather than,no less than,except,but等连接的短语时,谓语的形式依主语的单复数而定.
这句话的主语是“my mother”,后跟with连接的短语“with me”,所以谓语应该是B flies