Metals experience plastic deformation when a. their crystal patterns have been disrupted by stress
b. electrons have jumped up to the conductive area
c. an electric field has been applied
d. they are immersed in water

Option (A) is the correct answer.

Explanation:

Plastic deformation is the change in shape of an object or metal caused by the load of excess stress.

Thus, metals experience plastic deformation when their crystal patterns have been disrupted by stress.

When stress is provided to the metal then their crystal pattern gets deformed resulting in change of shape of the metal. Plastic deformation is a permanent deformation.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.