Being articulate has been equated with having a large vocabulary. Actually, however, people with large vocabularies have no incentive for, and tend not to engage in, the kind of creative linguistic self-expression that is required when no available words seem adequate. Thus a large vocabulary is a hindrance to using language in a truly articulate way. Which one of the following is an assumption made in the argument? ['In unfamiliar situations, even people with large vocabularies often do not have specifically suitable words available.', 'In educating people to be more articulate, it would be futile to try to increase the size of their vocabularies.', 'When people are truly articulate, they have the capacity to express themselves in situations in which their vocabularies seem inadequate.', 'The most articulate people are people who have large vocabularies but also are able to express themselves creatively when the situation demands it.']