The correct option is C Parathyroid gland
Symptoms of tetanus include
a)Tetanus often begins with mild spasms in the jaw muscles known as lockjaw. The spasms can also affect the facial muscles and experience spasms and stiffness in various muscles, especially those in jaw, abdomen, chest, back, and neck.
b)Muscle cramps or spasms in your legs, fever, high blood pressure etc
Hypoparathyroidism is decreased function of the parathyroid glands with underproduction of parathyroid hormone. This can lead to low levels of calcium in the blood, often causing cramping and twitching of muscles or tetany (involuntary muscle contraction).
Hence parathyroid gland is associated with tetanus.
So, the correct answer is 'Parathyroid gland'.