The correct answer is D. Flexibility.
A satisfactory quantitative method should be appropriate, measurable, and comparable. It should also be flexible enough to be adapted to different situations. However, it should not be so flexible that it loses its accuracy or reliability.
Appropriateness refers to the suitability of the method for the specific research question being asked. The method should be able to provide the necessary data and insights to answer the question.
Measurability refers to the ability to quantify the data collected using the method. The data should be precise and accurate enough to be meaningful.
Comparability refers to the ability to compare the data collected using the method to other data sets. This allows for the identification of trends and patterns.
Flexibility refers to the ability of the method to be adapted to different situations. This is important because research often takes place in real-world settings that are not always ideal.
A satisfactory quantitative method should possess all of these qualities. However, if a method is too flexible, it may lose its accuracy or reliability. This is because flexibility can lead to errors in data collection or analysis. Therefore, a satisfactory quantitative method should not be too flexible.