Which method involves using conversion factors and canceling units to calculate medication dosages?

Rationale: A. The direct calculation method involves using a simple formula based on the ratio of the desired dose to the available dose, without necessarily applying conversion factors or unit cancellation systematically. B. The dimensional analysis method, also known as the unit factor method, uses conversion factors and systematic cancellation of units to ensure that the final answer is expressed in the correct dosage units. This method reduces calculation errors by tracking units through each step of the calculation and is especially useful when converting between milligrams, milliliters, or other measurement systems. C. The desired-over-have method (also called the ratio method) sets up a proportion comparing the dose ordered to the dose available, which works well for straightforward calculations but does not inherently involve unit conversion or cancellation. D. While similar to the desired-over-have method, the ratio and proportion method sets up a proportion to solve for the unknown dose. It is effective for simple calculations but does not systematically use conversion factors or unit cancellation like dimensional analysis.