The passage implies that if hive temperature had not returned to normal by the end of the study in question, a probable conclusion of the researchers would have been that A. up-regulation of temperature is a preventative measure against chalk brood B. honeybees are incapable of purposely raising hive temperatures C. A. apis cannot be completely eradicated through up-regulation of temperature along D. honeybee larvae have a mechanism to alert adult honeybees to the presence of A. apis E. honeybee larvae may benefit from increased hive temperature even when there is no A. apis present