Which statement describes the difference between pre-emergent and post-emergent herbicides?

Which statement describes the difference between pre-emergent and post-emergent herbicides?

• A. Pre-emergents kill existing weeds; post-emergents prevent germination.
• B. Pre-emergents prevent germination; post-emergents kill existing weeds.
• C. They are the same in function.
• D. They only affect turf plants.

Answer: (B)