B, sodium nitrite is a carcinogen. Eating sausages processed by sodium nitrite will do harm to human health.
C baking soda, commonly known as sodium bicarbonate, is harmless to human body. Its aqueous solution is alkaline and easy to decompose when heated, which can make the baked cake loose and porous.
D, quicklime is the common name of calcium oxide, which can absorb water and can be used to dry food.
Therefore, choose: B.