Which class of drugs is most effective in significantly decreasing gastric acid secretion?

Explanation

Among the options, H2 histamine receptor antagonists are the most effective at reducing gastric acid production by blocking histamine action on parietal cells. H1 blockers primarily affect allergic responses, corticosteroids do not directly reduce acid secretion, and anticholinergics have a less potent effect on gastric acid. Proton pump inhibitors, although effective, were not listed as the correct choice here.