I believe the correct answer from the choices listed above is option B. The correct sentence would be "If she doesn't graduate in December, she willgraduate in June." This is the only sentence where the comma is in the right place while the others are wrongly placed.
The correct answer of the given question above would be option D. The correct description of one of the ways in which a command economy differs from a market economy is that, in a command economy, individuals have less economic freedom. Hope this answer helps.
