To find the inequality that shows how much time the dehumidifier can run before it becomes full, we need to consider the fact that the dehumidifier removes 1.6 pints of water per hour and can hold a maximum of 40 pints.
Let \( h \) represent the number of hours the dehumidifier runs. During these \( h \) hours, the total amount of water removed can be expressed as \( 1.6h \). We want this amount to be less than or equal to the maximum capacity of the dehumidifier, which is 40 pints.
Thus, the inequality that represents this situation is:
\[ 1.6h \leq 40 \]
This corresponds to Option #2.
Therefore, the answer is:
Option #2.