A fine white powder

"A fine white powder which is odorless" = not c, salt is not a fine powder, it should be a crystal.

"dissolved in water" = not a and not d, they don't dissolve in water.

"bubbled when mixed with vinegar" = b, active ingredient in baking powder is CO3- , it chemically change to CO2, which is the bubble

So, answer should be b. baking soda