A patient needs 0.1 mg of a drug. If each tablet is 0.025 mg, how many tablets are required?

To determine how many tablets are needed for a dose of 0.1 mg when each tablet contains 0.025 mg, you start by calculating the total amount of drug provided by a specific number of tablets.

First, divide the total required dose by the amount in each tablet:

0.1 mg (needed dose) ÷ 0.025 mg (per tablet) = 4 tablets.

This calculation shows that to achieve the desired dose of 0.1 mg, you would require 4 tablets of 0.025 mg each. This correctly reflects the relationship between the total dose and the dosing per tablet.

By accurately performing this division, it becomes clear that option C, which states 4 tablets, is indeed the necessary amount for the required medication dosage.