Why Does the narrator tell the officers to tear up the planks and therefore unveil the corpse

b. because he believes they hear the heartbeat and are mocking him

Explanation:

In the short story, The Tell-Tale Heart by Edgar Allan Poe, the narrator kills an old man because he hates his eye and then proceeds to cut him up and bury him beneath the floorboards.

When the police comes and they are having a chat, the narrator starts believing that he is hearing the heartbeat of the man he just murdered but the policemen are hearing nothing.

In despair, he confesses and tells the officers to tear up the planks to reveal his dastardly deed to prove that the man's heart was still beating and that the policemen could hear it too but choose to mock him by feigning ignorance.