A computer maker receives parts from three suppliers, S1, S2, and S3. 20\% come from S1, 30\% from S2, and 50\% from S3.
Among all the parts supplied by S1, 1\% are defective. For S2 and S3, the portion of defective parts is 4\% and 7\%, respectively
Let D = defective part, then P(S2) is