Which of the following has a crystalline appearance? baking soda salt baking powder corn starch

Salt has a crystalline appearance.

Salt is a mineral that is composed of sodium chloride. It has the chemical formula NaCl. Naturally, it is found as crystal also known as halite or rock salt.

Sea water is considered to be a main mineral constituent as it contains very large amounts of salt.

On the other hand:

Baking soda/baking powder is a white powder

Corn starch is a fine, white powder with no odor.