If the code for $\text{CAT}$ is $\text{DBU}$, what is the code for $\text{DOG}$?

Let's investigate the pattern connecting each letter of the word $\text{CAT}$ to its code $\text{DBU}$:
* $C\stackrel{+1}{\to }D$
* $A\stackrel{+1}{\to }B$
* $T\stackrel{+1}{\to }U$

The rule is to shift each letter forward by $+1$ in the alphabetical order. Applying the same rule to $\text{DOG}$:

* $D\stackrel{+1}{\to }E$
* $O\stackrel{+1}{\to }P$
* $G\stackrel{+1}{\to }H$

Thus, the code for $\text{DOG}$ is $\text{EPH}$.