BUTLER serves in restaurant and BUTLER is called ROGUE. So, ROGUE will be served in restaurant.

The last four letters of word are written in reverse order, followed by first three letters in same order. In group of letters so obtained, each letter except middle letter is moved one step backward while middle letter is moved one step forward to get code.
Thus, we have :
SUPREME => SUP/REME => EMER/SUP => DLD/SRTO.

Each letter in word is replaced by a set of two letters - one preceding it and or following it - in code. Thus, T is replaced by SU, R is replaced by QS and so on.

Each letter in word is replaced by letter which occupies same position from or end of alphabet, to obtain code.

Since every alternative letter starting from B of English alphabet is written in small letter, letters written in small letter are b, d, f, h and so on. And Capital letters are C, E, G so on.

In option first, third and fourth e is written in small letter, so it cannot be answer And In second option second e is written in small. Therefore, none of above options are satisfy condition. .

In right side of question re is a gap of 7 letters between B and J and 6 numbers between 6 and 14. Similarly, re is a gap of 3 letters between J and N. Therefore 3 numbers gap after 14 is 18.
In left side of question re is a gap of 8 letters between D and M and 6 numbers between 8 and 17. Similarly, re is a gap of 5 letters between M and S. Therefore 5 numbers gap after 17 is 23.

The word is divided into groups of two letters each and n letters of each group are written in a reverse order.

The last letter of word remains unaltered in code. The first six letters of word are divided into two groups of three letters each and n, in each group, last two letters are written in a reverse order.

The code is formed by first writing last three letters of word in a reverse order, followed by first three letters in same order. So, code for STUPID should be DIPSTU.

The letters in first half and second half of word are written n reverse order and n in group of letters so obtained, first, third, fifth and seventh letters are each moved one step forward while second, fourth, sixth and eighth letters are each moved one step backward to get code.
Thus, we have :
TRIANGLE => TRIA/NGLE => AIRT/ELGN => BHSSFKHM.