A student takes about 4 mL of distilled water in four test tubes marked P,Q,Rand S. He then dissolves in each test tube an equal amount of one salt in one test tube, namely sodium sulphate in P, potassium sulphate in Q, calcium sulphate in R and magnesium sulphate in S. AFter that he adds on equal amount of soap solution en each test tube. on shaking each of these tubes well, he observes a good amount of lather in the test tubes marked

Options

A. P and Q
B. Q and R
C. P,Q and S
D. P,R and S