To answer this question, let's go through each option to understand why it is correct or incorrect:
Option A) SELECT ADD_MONTHS(MAX(hire_Date), 6) FROM EMP;
This option calculates the maximum hire date from the EMP table and adds 6 months to it using the ADD_MONTHS function. The result is a date value, not a numeric value.
Option B) SELECT ROUND(hire_date) FROM EMP;
This option rounds the hire_date column values to the nearest whole number. The result is a date value, not a numeric value.
Option C) SELECT sysdate-hire_date FROM EMP;
This option subtracts the hire_date column values from the current date (sysdate) using the minus operator. The result of this subtraction operation is a numeric value representing the number of days between the hire date and the current date.
Option D) SELECT TO_NUMBER(hire_date + 7) FROM EMP;
This option adds 7 days to the hire_date column values and then converts the result to a numeric value using the TO_NUMBER function. The result is a numeric value.
The correct answer is option C. This option returns a numeric value because it calculates the number of days between the hire date and the current date.