The most appropriate piece of evidence to support the author's claim that no one should attempt to do any yard work in cold weather is B. Yard work in cold weather is difficult because the ground is too hard and frozen.
This option provides a concrete reason related to the physical conditions of yard work in cold weather, reinforcing the argument that it is impractical (and therefore not advisable) to engage in yard work under such circumstances. Options A, C, and D do not directly support the idea that yard work should not be done in cold weather.