Answer:
Bandwagon advertising
Step-by-step explanation:
According to the given excerpt, an advertising company made a claim that its mascara was "America's favorite mascara." and claimed that it was immensely popular because it was a great product and also because of patriotism.
Propaganda advertising is a technique which is used to emotionally influence people's behaviors and opinions.
The propaganda technique that is used in the statement is Bandwagon advertising.
Bandwagon advertising is a specific type of propaganda advertising technique that attempts to make the target customers to want to be a part of what they are offering so as not to be "left out" as so many other people were already using the product.