Final answer:
When faced with a missing route of administration for an antibiotic, a pharmacy technician should communicate with the pharmacist to gain clarification.
Step-by-step explanation:
As a pharmacy technician, when faced with a missing route of administration for an antibiotic, it is important to communicate with the pharmacist to report the missing information and gain clarification (option b). Guessing the route of administration (option a) may lead to ineffective treatment or potential harm to the patient. Preparing the antibiotic for all types of administration routes (option c) may result in unnecessary wastage of medication. Asking the patient for their preference (option d) is not recommended as it should be determined by the healthcare professional based on the patient's condition and the most appropriate route.