Which SQL statement will return the ENAME, length of the ENAME, and the numeric position of the letter …?

The EMPLOYEES table contains these columns:
EMPLOYEE_ID NUMBER(4)
ENAME VARCHAR2 (25)
JOB_ID VARCHAR2(10)
Which SQL statement will return the ENAME, length of the ENAME, and the numeric position of
the letter “a” in the ENAME column, for those employees whose ENAME ends with a the letter
“n”?

A.
SELECT ENAME, LENGTH(ENAME), INSTR(ENAME, ‘a’) FROM EMPLOYEES WHERE
SUBSTR(ENAME, -1, 1) = ‘n’;

B.
SELECT ENAME, LENGTH(ENAME), INSTR(ENAME, ,-1,1) FROM EMPLOYEES WHERE
SUBSTR(ENAME, -1, 1) = ‘n’;

C.
SELECT ENAME, LENGTH(ENAME), SUBSTR(ENAME, -1,1) FROM EMPLOYEES WHERE
INSTR(ENAME, 1, 1) = ‘n’;

D.
SELECT ENAME, LENGTH(ENAME), SUBSTR(ENAME, -1,1) FROM EMPLOYEES WHERE
INSTR(ENAME, -1, 1) = ‘n’;

Explanation:
INSTR is a character function return the numeric position of a named string. INSTR(NAMED,a)
Incorrect answer:
BDid not return a numeric position for a.
CDid not return a numeric position for a.
DDid not return a numeric position for a.
Refer: Introduction to Oracle9i: SQL, Oracle University Study Guide, 3-8