How did the patient likely inhale the poison if they are coughing blood after a chlorine tank rupture?

The correct choice indicates that the patient likely inhaled the poison, which is consistent with the symptoms presented after a chlorine tank rupture. Chlorine is a highly toxic gas that can cause lung irritation and damage when inhaled. In the scenario, the release of chlorine vapor would create a hazardous environment where individuals in proximity could breathe in the harmful gas.

Coughing up blood, also known as hemoptysis, can occur as a result of the severe irritation and injury that chlorine can cause to the respiratory tract and lung tissue. The inhalation of the gas can lead to inflammation, chemical burns in the airways, and bleeding, which would explain the patient's symptoms.

The other methods of exposure—ingestion, absorption, or injection—are not relevant in this case due to the specific nature of the chlorine gas release. Inhalation is the primary route through which the patient would have come into contact with the poisonous substance, leading to the observed coughing of blood.