The correct answer is C. The correct spelling of the word is “Thallium”.
A. Tenure is the length of time that someone holds a job or position.
B. Trigonometry is a branch of mathematics that deals with the relationships between the sides and angles of triangles.
D. Turquoise is a blue-green gemstone.
Thallium is a chemical element with the symbol Tl and atomic number 81. It is a soft, silvery-white metal that is chemically similar to lead and bismuth. Thallium is a highly toxic element that can cause severe health problems, including death.