Select the alternative that is related to the third term in the same way as the second term is related to the first term.
AB : DH :: DE : ?

Let's analyze the alphabetical ranks of the first pair ($\text{AB}:\text{DH}$):
* $\text{A}(1)\to \text{D}(4)⟹1\times 4=4$
* $\text{B}(2)\to \text{H}(8)⟹2\times 4=8$
The rule multiplies the alphabetical position value of each letter by $4$.

Applying this same rule to $\text{DE}$:

* $\text{D}(4)\times 4=16\to \text{P}$
* $\text{E}(5)\times 4=20\to \text{T}$

Thus, the missing term is $\text{PT}$.