Which revision would BEST improvement of this sentence in paragraph 2

Which of the following sentences most clearly uses topical organization? a. do you have problems with mosquitoes and gnats? fabulous exterminators can ! b. we've gathered at this conference to discuss three things: poverty, war, and disease. c. killer bees have spread up from south america into mexico and the united states. d. first, gather all the painting supplies you need. next, lay them out on a work bench.