Three test tubes, X, Y and Z, are each filled with water. A small quantity of NaCl is then put into test tube X. A small quantity of SiCl$_4$ is then put into test tube Y. A small quantity of AlCl$_3$ is then put into test tube Z. After a brief period, two drops of universal indicator solution are added to each test tube. Which of these statements could be correct?
- A1, 2 and 3
- B1 and 2 only
- C2 and 3 only
- D1 only