Which statement best contrasts 401 and 403 responses?

Which statement best contrasts 401 and 403 responses?

• A. 401 indicates missing or invalid authentication credentials.
• B. 403 indicates missing or invalid authentication credentials.
• C. 401 indicates the resource does not exist.
• D. 403 indicates the request is malformed.

Answer: (A)

Understanding HTTP status codes: 401 and 403 distinguish authentication from authorization. The statement that 401 indicates missing or invalid authentication credentials aligns with how the protocol treats unauthenticated requests—the server is asking the client to provide valid credentials, often with a WWW-Authenticate challenge. On the other hand, 403 means the request was authenticated but the user does not have permission to access the resource, so even valid credentials won’t grant access. The other options mix up concepts: a missing resource is 404, and a malformed request is 400. So this interpretation best contrasts the two responses.

Understanding HTTP status codes: 401 and 403 distinguish authentication from authorization. The statement that 401 indicates missing or invalid authentication credentials aligns with how the protocol treats unauthenticated requests—the server is asking the client to provide valid credentials, often with a WWW-Authenticate challenge. On the other hand, 403 means the request was authenticated but the user does not have permission to access the resource, so even valid credentials won’t grant access. The other options mix up concepts: a missing resource is 404, and a malformed request is 400. So this interpretation best contrasts the two responses.