In acetain code MAIN is written as IMNA and REAL is written as ARLE. How is LION written in that code ?

The correct answer is (c) OLNI.

In the given code, the first and third letters of the original word are swapped, and the second and fourth letters are kept the same.

For example,
* MAIN becomes IMNA
* REAL becomes ARLE
* LION becomes OLNI

The other options are incorrect because they do not follow the given rule.
* (a) 1LON: The first and third letters of LION are not swapped.
* (b) NIOL: The second and fourth letters of LION are not kept the same.
* (d) OINL: The first and third letters of LION are not swapped, and the second and fourth letters are not kept the same.