Final answer:
The 'Auxiliary label' should be used on Doxycycline, providing additional information about the medication.
Step-by-step explanation:
The 'Auxiliary label' should be used on Doxycycline.
The 'Auxiliary label' is an important component of medication labeling that provides additional information about the medication.
In the case of Doxycycline, the 'Auxiliary label' would typically indicate warnings or precautions, such as avoiding sunlight exposure or taking the medication with food.