Answer:
Formalin.
Explanation:
Formalin is a mixture if formaldehyde and water. 37% formalin is commonly used in the market. The formula of formaldehyde is HCHO.
Formalin acts as a strong disinfectant and can cause tissue hardening. Hence, Formalin is used to preserve the biological specimen and a specimen can be sent for permanent section.
Thus, the correct answer is option (C).
