Mr. winters was having a roach problem in his classroom. he bought a product to kill the roaches. the advertisement said that the roach spray would be effective for at least one month. mr. winters and his class kept data on the roaches in the classroom after spraying. based on the results, what could mr. winters infer about the roach spray? a) the spray did not kill any roaches. b) the spray worked, but only for about 10 days. c) the spray kept the roach population down for 21 days. d) the spray worked just like the advertisement said it would.