Answer:
The correct answer will be option-D.
Step-by-step explanation:
The scientific method is the systematic approach to understand, answer and explain the natural events.
The method involves the steps performed in the sequences which begins with the making observation, asking a question, do background research, proposing a hypothesis and performing experiments.
In the given question, the option which asks the amount of water to make plastic bag can be answered using scientific method as background research will help predict the hypothesis and the experiments can be designed and performed.
Thus, option-D is the correct answer.