To solve this question, the user needs to know the different flags that can be set when creating a cookie and their purposes.

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

A. Safe: This flag indicates that the cookie should only be sent over an encrypted channel. It does not protect against other types of attacks such as cross-site scripting (XSS) or cross-site request forgery (CSRF). Therefore, this option is not correct for this question.

B. Protected: This flag is not a standard cookie flag. Therefore, this option is not correct for this question.

C. Locked: This flag is not a standard cookie flag. Therefore, this option is not correct for this question.

D. Secure: This flag indicates that the cookie should only be sent over an encrypted channel and helps protect against attacks such as XSS and CSRF. This is a good programming practice to ensure that sensitive information transmitted over cookies is secure. Therefore, the correct answer is:

The Answer is: D