A 23-year-old man has been treated with cimetidine for 6 months What is the mechanism of action of this drug?

A 23-year-old man has been treated with cimetidine (Tagamet) for 6 months.
What is the mechanism of action of this drug?

A-Adds a protective membrane to gastric mucosa
B-Blocks the secretion of hydrochloric acid
C-Neutralizes gastric acidity
D-Stimulates H2 receptors