"In fact" makes no sense here. The only option which fits is "Even".

Sasha, arguments can be made in favor of using 'in fact' and 'even'. Personally, I believe that 'in fact' is the correct phrase to use here. The reason is because all the sentences before (6) are building up the argument of how convenient and relaxing a shopping experience can be in the US. And then to further support this argument, sentence (6) states: In fact! in small stores, the price is always clearly marked on the product, and that’s the price you pay (so you don't have to spend any energy thinking and calculating, but instead simply remain worry free and relaxed). Why I wouldn't use the phrase 'even': 1) Prices and big stores haven't been mentioned prior to statement (6). 2) The sentence before statement (6) talks about confusion. Then, statement (6) mentions how prices are always clearly marked. Thus no confusion.

"However" conveys a contradiction or contrast. For example: "I love shopping for other people. However, I hate shopping for my dad because he has everything he wants or needs." "Even" shows that something is still true in cases where you might expect the opposite. For example: "I'll buy anything you try to sell me. Even if I don't want it, I'll still buy it." "Buy" isn't a discourse marker but a verb, and doesn't fit the flow of information. "In fact" is used to show an example or illustration of what was said previously. For example: "I love shopping for clothes. In fact, I could spend all day doing it." So in this paragraph, the author is talking about shopping malls and the culture of shopping among Americans. It explains that Americans don't like to be bothered by store employees unless they have a question or need help. To illustrate this, it gives the example of how small stores have the price tag marked on the products. So should we use "even" or "in fact"? Well, in my opinion, it's not very clear in this case. 1) Does the author wish to simply give an example to illustrate his/her point that Americans don't like to be bothered while shopping? Or 2) does the author wish to show that in small stores, where you might expect to have more interaction with employees, and more flexibility with pricing, there are still fixed prices tagged on the products? Neither of those is clear given the context. I think what is confusing about it for me, as an American, is that in America the price is clearly marked in both large stores and small stores, and as someone who lives abroad, I also know it doesn't always work that way in other countries. So the more I look at it, the more I think it should be "Even." So in summary, the sentence has two potentially correct answers and therefore isn't a very well designed assessment. If you chose "even" or "in fact" you'd be right in both cases. As a writer and a native speaker, I personally like "Even" better