Under CPLR, how can a summons be served?

The correct choice reflects the provisions of the Civil Practice Law and Rules (CPLR) regarding the methods by which a summons can be served. Under CPLR, a summons may be served through several mechanisms: personal delivery to the defendant, substituted service (which typically involves serving someone of suitable age and discretion at the defendant's residence or place of business), or by mail provided that an acknowledgment of receipt is returned.

This flexibility in service preserves the rights of both parties by ensuring that a defendant is properly notified of the legal proceedings against them while also accommodating various scenarios that may prevent personal delivery. The ability to service by mail, specified with the condition of obtaining an acknowledgment, helps in situations where direct delivery is impractical.

The other options suggest more restrictive methods of serving a summons that do not encompass the full range of acceptable strategies outlined in the CPLR. This versatility is crucial in effectively administering justice and ensuring that defendants receive proper notice without being hampered by rigid procedural limitations.