Answer:
Denaturation.
Explanation:
Denaturation may be defined as the process at which the proteins are placed at the unfavorable environment. The proteins are treated at high temperature, pressure and the in the presence of different chemicals.
The high temperature changes the three dimensional shape of the protein and unfold the native state of the protein. This result in the loss of the biological activity of the protein. Renaturation of protein is possible only if the primary structure of the protein is not destroyed.
Thus, the correct answer is option (3).