The Palace Museum is the best place _______I've ever visited. There are many old things in it

A. who  B. that C. where

Online shopping has become something very common for young people, however, it's not easy for the old people to buy things on the internet. Therefore, offline Daigou stores, or buy-for-you stores, are becoming popular among the old.
64-year-old man Li Hui'an is searching for his favorite CD in an offline Daigou shop. He says, "It's very convenient to buy things online, however, I can't use the internet. After I happened to find this buy-for-you shop, I decided to try, as I wanted to buy an opera CD. Finally I got one I'd searched for several years. I was so happy. I have become crazy about offline shopping. "
The store owner Liu Min says in order to meet the need of people who want to buy things online but can't use the internet, she started the business of offline buy-for-you. In only about ten days since the start of the business, she has received more than 20 orders from customers (顾客). Liu Min is not the only one who finds the large need of offline buy-for-you business in the market. In Dalian city, northeast China, more than 300 such stores opened their doors only in April.
In order to attract more customers, they have opened their shops in residential communities (居民区). And they charge a suitable service fee. For example, when buying things that cost less than 200 Yuan for customers, they usually charge 5 Yuan as service fee.
Though the offline buy-for-you service makes it easier for certain people to shop online, what if there is any problem with the ordered thing, let's say, like a quality problem? The shop owners say they will deal with any quality problems that may happen when using their Daigou service.
【小题1】What is offline shopping?