Lily is going to travel to Yunnan with her family in the summer vacation. The map to refer to when determining the itinerary is () A. Yunnan tourist attractions B. Traffic map C. Guide.

In the huge map family, there are natural maps and socio-economic maps. Natural maps include topographic maps, climate maps, hydrological maps, vegetation maps, etc. Social and economic maps include industrial maps, agricultural maps, commercial maps, traffic maps and population distribution maps. According to the functions of various maps, it is necessary to refer to the traffic map when determining the itinerary.

Therefore, choose: B.