To answer this question, the user needs to have knowledge about HTTP response status codes. The HTTP response status code indicates whether a request has been successfully completed or not. It is a 3-digit integer with the first digit indicating the general response class, while the last two digits do not have any categorization role.

Now, let's go through each option and explain why it is right or wrong:

A. A status of 200 to 299 signifies that the request was successful - This statement is correct. HTTP status codes 2xx indicate that the request was successfully received, understood, and accepted.

B. A status of 300 to 399 are informational messages - This statement is incorrect. HTTP status codes 3xx indicate redirection messages, not informational messages.

C. A status of 400 to 499 indicates an error in the server - This statement is incorrect. HTTP status codes 4xx indicate client errors, not server errors.

D. A status of 500 to 599 indicates an error in the client - This statement is incorrect. HTTP status codes 5xx indicate server errors, not client errors.

Therefore, the correct answer is:

The Answer is: A.