I got is right but imho all the answers as given are wrong.

Varchar does not just use the space required for the number of characters in the row. It is important to remember that varchar has a length prefix, and that a varchar field uses the data entered plus 2 bytes. I have seen some poor database designs that have ignored this fact, with varchar(1), varchar(2), etc fields.

Another important thing to remember is that varchar uses more space in an index than does a char column. Ther are also limitation about using varchar columns in an index if the varchar data has gone into overflow pages.

So, there is a lot more to the differences between char and varchar than allowed for in the answers in the question. If the question had included a 'none of the above' option I would have chosen that as the answer.