Which of the following is an example of a single dose rodenticide?

Red squill is indeed an example of a single dose rodenticide. This means that when ingested, it is designed to be lethal to rodents after a single feeding. Red squill contains a toxic compound derived from the red squill plant, which has been used historically to control rodent populations effectively.

In contrast, warfarin, while used for rodent control, operates as an anticoagulant that typically requires multiple doses over time to be effective, thereby classifying it as a multiple dose rodenticide. Malathion and chlordane are both insecticides rather than rodenticides, targeting insects rather than rodents. They work through different mechanisms and are not intended for rodent control, reinforcing that red squill is the only correct answer in this context.