In a certain code THRIVES is written as SIUHRDU. How is SOULFUL written in that code ?

The word THRIVES is divided into three pars : THR , I , VES

I : THR - SIU

The diagonally opposite element is substituted by its immediate following alphabet in the English alphabetical series.

=> T is substituted by U at its diagonally opposite position. Similarly H is substituted by I at its diagonally opposite position and R by S.

II : I - H

The middle letter is substituted by its immediate preceding alphabet in the English alphabetical series.

III : VES - RDU

The diagonally opposite element is substituted by its immediate preceding alphabet in the English alphabetical series.

=> V is substituted by U at its diagonally opposite position. Similarly E is substituted by D at its diagonally opposite position and S by R.

Thus, code for SOULFUL :

SOU - VPT

L - K

FUL - KTE

$$\therefore$$ SOULFUL - VPTKKTE