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