How do rodenticide tracking powders kill rodents that consume them?

Rodenticides in tracking powder form are designed to kill rodents primarily when they ingest the powder while grooming themselves. As rodents clean their fur, they ingest the fine particles of the rodenticide that have settled on their bodies. This method is particularly effective because it leads to the consumption of the toxic substance directly, allowing it to enter the rodent's system and take effect.

The formulation of tracking powders ensures that the particles cling to the fur of the rodents as they move through treated areas. This creates a situation where, through their natural grooming behavior, they are likely to consume a lethal dose of the active ingredient in the powder. As a result, option B accurately reflects the critical mechanism by which these rodenticides operate.

Other methods such as inhalation of the dust or coating tails for paralysis do not accurately describe the intended use and effectiveness of rodenticide tracking powders. The primary action is based on the rodent ingesting the powder through grooming, making this method efficient for targeting rodent populations.