Which of the following actions is required for humanely destroying reactors?

The correct action required for humanely destroying reactors is to follow the guidelines set by M.G.L. 129, §44A. This law provides specific regulations to ensure the humane treatment of animals that may be suffering from certain diseases. It is vital to adhere to these legal and ethical guidelines to ensure that the destruction process is carried out in a manner that minimizes suffering and complies with state laws.

By following these guidelines, the actions taken align with humane treatment standards and ensure that the procedure is conducted properly by qualified individuals who understand the importance of considering the welfare of the animals involved. This legal framework is in place to protect both the animals and the interests of the public, ensuring that humane practices are universally observed.

The other options do not align with these mandatory requirements, as selling the animal or sending it to an auction house does not prioritize humane practices, nor do retesting protocols specifically address the ethical considerations involved in humane destruction.