a is chemically wrong. NiClx is the right formula for nickel chloride which x is the molecular number associated with Ni. x is usually 2. A is wrong.
It is not pepper. Pepper has a chemical formula of C17H19NO3 which is not really very common. B is not right.
It is not sugar. Sugar contains hydrogen oxygen and Carbon in some combination. So it's not D.
Answer C Salt. <<<< answer.
