Explanation:
This is the correct solution for the answer.

 GRANT role_name TO users; 

Incorrect answer :
1: there is no such MODIFY keyword
2: invalid CREATE command, there is no such NEW keyword
3: invalid GRANT command, there is no such ROLE keyword
5: invalid GRANT command, there is no such CHANGE keyword
Reference:
Introduction to Oracle9i : SQL, Oracle University Study Guide, 13-10

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