Identify the sentence that is correctly punctuated.

A. Clara did not study very much for her biology test, therefore, she guessed at many of the answers.
B. Clara did not study very much for her biology test; therefore she guessed at many of the answers.
C. Clara did not study very much for her biology test; therefore, she guessed at many of the answers.
D. Clara did not study very much for her biology test, therefore; she guessed at many of the answers

C

3 answers

Not C.
B is right.
Use a comma after a transitional expression of two or more syllables; therefore, the correct answer is C.