Answer:
D. Designing experiments
Step-by-step explanation:
Scientists get understanding of the world by performing experiments. Direct conclusion without any data is considered as irrelevant. The scientists design the protocol of the experiment and performs it accordingly to get the data and then infer the result from it.
The experiments are designed on the basis of the hypothesis being stated. The hypothesis is validated by the experiments and has to be altered or withdrawn if the results do not support the hypothesis.