Which Pair Offers the Best Example of Competence and Performance

Multiple Choice

Which pair offers the best example of competence and performance, respectively?

A) Distinguishing grammatical sentences from ungrammatical ones; being able to speak grammatically
B) Being able to write grammatical sentences; explaining the rules of grammar to your friend
C) Speaking a foreign language; reading a foreign language
D) Speaking a foreign language; understanding what is said in a foreign language