Answer:
B. Water
Step-by-step explanation:
A: Salt
Salt disperses heat and minimizes oxygen supply to a fire. This is especially useful if you experience a grease fire on or around the oven. Salt is also one of the main ingredients found in fire extinguishers.
Total Fire Group has a list of other things that can put out a fire
B: Water
Class B fires are made up of flammable liquids. If you were to throw water on a Class B fire, you might very well remove the heat and extinguish the fire but you would be equally likely to cause the flammable liquid to spray all over the place while it is on fire.
Firefighter Inside has an amazing article on the classes of fire, how to put them out, and why certain things (like water) can't be used to put out certain types of fires.
C: Sand
Sand suffocates the fire getting rid of the oxygen supply to the fire. and when the fire has no more oxygen it goes out.
Hunker has an article on how to put out a fire with a bucket of sand
D: Baking soda
Baking soda is good for putting out small fire cause the powder suffocates it and the bicarbonate in baking soda creates a chemical reaction when it gets hot enough that it starts to produce carbon dioxide, carbon dioxide removes oxygen from the fire causing the fire to go out.
Firefighter Now has a better and more detailed explanation on baking soda.