Final answer:
Chlorpheniramine is likely to cause the most sedation.
Step-by-step explanation:
Chlorpheniramine is an antihistamine medication that is commonly used to relieve symptoms associated with allergies. It belongs to the first-generation antihistamine class and is available over-the-counter in many formulations.
Among the given options, chlorpheniramine is likely to cause the most sedation. Chlorpheniramine is a first-generation antihistamine that exhibits sedating effects due to its ability to readily cross the blood-brain barrier. It works by blocking the H1 receptors in the brain, resulting in sedation and drowsiness.