Which of the Following Statements About Colloquialisms Is True

Which of the following statements about colloquialisms is true?

A) Unfamiliar colloquialisms can cause problems even for native English speakers.
B) Colloquialisms are generally easy for international communicators to understand.
C) Colloquialisms are almost never defined on ESL websites.
D) In the United States, colloquial expressions are rarely used.
E) It is impossible to replace colloquialisms with plain language.