Tetany is caused by:

 # Tetany is caused by:

A. Hyperglycemia 

B. Hypocalcemia 

C. Clostridium tetani 

D. Low oxygen level

The correct answer is B. Hypocalcemia.

Tetany is a condition characterized by involuntary muscle contractions, cramps, and spasms. The primary cause of tetany is hypocalcemia, which is a low level of calcium in the blood. Calcium plays a crucial role in muscle contraction and nerve function. When calcium levels are low, nerves become hyperexcitable, leading to the uncontrolled muscle contractions seen in tetany.

Hyperglycemia (A): High blood sugar levels are associated with diabetes, not tetany.

Clostridium tetani (C): This bacterium causes tetanus, a different condition characterized by muscle stiffness and spasms.

Low oxygen level (D): While low oxygen can cause various symptoms, it is not the primary cause of tetany.

Reference: Hypocalcemia and Tetany: Causes, Symptoms, and Treatment (webmd.com)