Final answer:
Ampicillin sodium is the generic name for the drug listed among the options, which is the standard name used in the medical community.
Step-by-step explanation:
The generic name of a drug is the standard name without any brand affiliation, typically a name rooted in the drug's chemical composition or pharmacological properties. When looking at the options provided (Ampicillin sodium, SK Ampicillin-N, Polycillin-N, and Omnipen-N), the name that stands out as the generic name is Ampicillin sodium. The other options are brand or trade names that are more marketing-driven and contain additional identifiers such as capital letters, hyphens, or suffixes (like "-N") which are often associated with brand names.