Q31. Hospital trauma centers are given ratings depending on their capabilities to treat various traumas. Suppose that the metropolitan area has a level 1, a level 2, and a level 3 trauma center. We wish to take samples of patients from these trauma centers in such a way that the total sample size is 30 and covers each trauma centers equally. What sampling technique should we apply?a. Simple Random samplingb. Systematic samplingc. Cluster samplingd. Stratified sampling