Correct Response: A. The test tube is not in direct contact with a heating surface, and the test tube is oriented away from people. This precaution is important in case of splashing, glass breakage, etc. Having the test tube in the flame could lead to glass breakage. B is incorrect because acetone is flammable and the beaker is in direct contact with a Bunsen burner. This would result in uneven heating and possible glass breakage and is a potential fire hazard. C is incorrect because NaClO reacts with HCl to produce chlorine gas. D is incorrect because transferring a beaker of boiling water directly into an ice bath could cause the beaker to break (resulting in spillage of boiling water).