If every requirement can be checked by a cost-effective process, then SRS is called

Explanation

IEEE 830 defines an SRS as verifiable if and only if every requirement stated in it is verifiable, and a requirement is verifiable if there exists some finite, cost-effective process by which a person or a machine can check that the product meets it. That is exactly the wording in the question. A traceable SRS lets each requirement be traced back to its origin and forward into the design and code; a modifiable SRS is structured so changes can be made easily and consistently; a complete SRS includes all significant requirements and responses. Only verifiability is about being checkable at reasonable cost.