Which of the following frequencies indicates medication should be taken continuously throughout the day?

The frequency indicated by taking medication "q4h" means that the medication should be taken every four hours. This schedule allows for continuous therapeutic levels of the medication in the bloodstream throughout the day, as it requires dosing around the clock. This regular interval helps to maintain consistent drug levels, which is especially important for certain medications that require steady plasma concentrations to be effective, such as pain relievers or antibiotics in some cases.

In contrast, the other options involve less frequent dosing. "bid" means taking the medication twice a day, which does not ensure continuous administration throughout the day. "qd" signifies once a day, limiting the frequency to just one dose within 24 hours. "qod," which stands for every other day, clearly does not provide continuous dosing, as it allows for extended gaps without medication administration. Thus, choosing the "q4h" frequency aligns with the requirement for continuous medication throughout the day.