What you are looking for is something from the left side of the periodic table (the metals), combined with something from the right side of the periodic table.
SiCl4 is something from the middle with something on the right. Not the answer.
HCl is a possible answer, but it is not the best one, because Hydrogen can be on both sides. It is not quite as willing to give up its electrons as the answer.
CCl4 has the same problem as A.
The answer is C
Ca is in column 2 just about as far left as you can get.
Cl is in column 17 which is just about as far right as you can get.