To solve this question, the user needs to know the SQL syntax for granting privileges to users and the difference between "ALL USERS" and "PUBLIC".

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

A. GRANT select ON dept TO ALL USERS; This option is incorrect because the correct keyword to grant privileges to all users is "PUBLIC" instead of "ALL USERS". Also, "QUERY" is not a valid keyword, and the correct keyword to grant query privileges is "SELECT". Therefore, option A is incorrect.

B. GRANT select ON dept TO ALL; This option is incorrect because the correct keyword to grant query privileges is "SELECT" instead of "QUERY". Also, "ALL" is not a valid keyword to grant privileges to all users, and the correct keyword is "PUBLIC". Therefore, option B is incorrect.

C. GRANT QUERY ON dept TO ALL USERS; This option is incorrect because "QUERY" is not a valid keyword to grant privileges, and the correct keyword is "SELECT". Also, "ALL USERS" is not a valid keyword to grant privileges to all users, and the correct keyword is "PUBLIC". Therefore, option C is incorrect.

D. GRANT select ON dept TO PUBLIC; This option is correct. The correct keyword to grant select (query) privileges is "SELECT". The keyword "PUBLIC" is used to grant privileges to all users. Therefore, option D is the correct answer.

The Answer is: D