Concept:
Hospital waste is broadly classified into:
• General healthcare waste (non-hazardous)
• Infectious waste
• Sharps
• Pharmaceutical waste
• Chemical waste
Most of the waste generated in hospitals is non-hazardous general waste produced from administrative, housekeeping, kitchen, and packaging activities.
Approximately 75--90% of hospital waste is general healthcare waste.
Step 1: Analyze option A.
Infected waste forms only a smaller proportion of total hospital waste.
Hence, option A is incorrect.
Step 2: Analyze option B.
General healthcare waste is produced in the largest quantity in hospitals.
Hence, option B is correct.
Step 3: Analyze option C.
Discarded medicines constitute only a limited fraction of biomedical waste.
Hence, option C is incorrect.
Step 4: Analyze option D.
Needles and scalpels belong to sharps waste and are generated in much smaller quantities.
Hence, option D is incorrect.
Therefore, the correct answer is:
\[
\boxed{(B)\ \text{General healthcare waste}}
\]