B, the density of carbon dioxide is eight times greater than that of air, so the method of upward gas collection is adopted, and the conduit should be close to the bottom of the container, which is convenient for discharging the air in the bottle, so b is correct;
C, alcohol lamp should be lit with a match, can't use alcohol lamp, easy to catch fire, so C is wrong;
A, when using the rubber eyedropper, it should be hung above the test tube, and it cannot be extended into the test tube, so A is wrong.
So choose B.