synchronous: Code execution must wait for an API call to return before continuing.

asynchronous: Code execution does not need to wait for an API call to return before continuing.

REST: Data is called indirectly using generic HTTP methods such as GET, POST, PUT, and DELETE.

RPC: Calls to request a service from a remote server must execute the same way as a request to the local system.

Comprehensive Detailed Step by Step Explanation with References

Synchronous:

Explanation: In a synchronous API call, the client must wait for the server to process the request and return a response before it can proceed with further execution.

Mapping: "Code execution must wait for an API call to return before continuing."

Asynchronous:

Explanation: In an asynchronous API call, the client can continue processing other tasks while waiting for the server to respond. This improves the efficiency and responsiveness of the application.

Mapping: "Code execution does not need to wait for an API call to return before continuing."

REST (Representational State Transfer):

Explanation: REST is an architectural style for designing networked applications. It relies on a stateless, client-server communication protocol, typically HTTP. RESTful APIs use standard HTTP methods (GET, POST, PUT, DELETE) to perform operations on resources.

Mapping: "Data is called indirectly using generic HTTP methods such as GET, POST, PUT, and DELETE."

RPC (Remote Procedure Call):

Explanation: RPC is a protocol that one program can use to request a service from a program located on another computer in a network. The calls are made in the same way as a local function call.

Mapping: "Calls to request a service from a remote server must execute the same way as a request to the local system."

References:

Cisco DevNet Associate Certification Guide, Sections on API styles and their characteristics

Official Cisco documentation on RESTful and RPC APIs

General programming resources on synchronous vs. asynchronous API calls

Therefore, the correct mapping is:

synchronous → "Code execution must wait for an API call to return before continuing."

asynchronous → "Code execution does not need to wait for an API call to return before continuing."

REST → "Data is called indirectly using generic HTTP methods such as GET, POST, PUT, and DELETE."

RPC → "Calls to request a service from a remote server must execute the same way as a request to the local system."