Explanation:
To achieve the result you must add 100 to sal before multiply with 12.

 SELECT ename, sal, 12*(sal+100) FROM EMP; 

Incorrect Answer:
1: Multiplication and division has priority over addition and subtraction in Operator precedence.
3: Give wrong results
4: Wrong syntax
Refer:
Introduction to Oracle9i : SQL, Oracle University Study Guide, 1-11

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