chemistry1111
Hey!
The trick to this question is to look at the ions available in each solution and check if something insoluble can be formed. For example, to check if A was the answer you would see if magnesium sulphate or potassium chloride is insoluble in water. If either one is, then that is a precipitate.
Edit: I see that you also asked this question here and it was answered. In future please try to avoid asking the same question in multiple places - otherwise it creates extra work for others.
