Can a Certified letter be insured?

A Certified letter cannot be insured. Certified mail provides proof of mailing and delivery but does not include insurance. It serves as a secure service that provides a verification trail by requiring the recipient's signature upon delivery. Although postal services offer options like insurance for certain packages and mail types, certification itself doesn't include this coverage.

The other choices suggest scenarios where insurance might apply—such as only applicable for international mail or for letters over a certain weight—but these are not accurate in the context of certified mail specifically. Certified mail focuses on tracking and delivery confirmation rather than providing any type of monetary coverage in case of loss or damage. Therefore, the statement that a Certified letter cannot be insured is correct.