Final answer:
The most popular method for submitting pharmacy transactions is Electronic Prescribing (e-prescribing), due to its efficiency and reduction in prescription errors.
Step-by-step explanation:
The most popular method of submitting pharmacy transactions is C) Electronic Prescribing (e-prescribing). This modern practice utilizes electronic data transmission to send prescriptions directly from the provider's office to the pharmacy. E-prescribing improves accuracy, reduces prescription errors, and streamlines the medication distribution process. While other methods such as fax, phone, and paper submissions are still in use, e-prescribing has become the preferred mode due to its efficiency and the benefits it offers in terms of healthcare management and patient safety.