Final answer:
The best tube for collecting an ethanol specimen is a blood tube containing K2EDTA to preserve the integrity of the ethanol and prevent clotting of the blood.
Step-by-step explanation:
The best tube for collecting an ethanol specimen would be a tube that is compatible with ethanol and can prevent contamination or evaporation. One commonly used tube for this purpose is a blood tube containing dipotassium ethylenediaminetetra-acetic acid (K2EDTA). K2EDTA helps to preserve the integrity of the ethanol in the specimen and prevent clotting of the blood. Other tubes, such as those containing heparin, can also be used depending on the specific requirements of the test.