Step-by-step explanation:
In a physical change the substance involved in the change is the same after and before it. We can change the temperature, the volume, the texture but not the substance.
In a chemical change, the substance changes. In a chemical reaction we start with reactants that are transformed into products that are different compounds from the reactants. But the atoms of the elements remains the same.
In nuclear change, it is all about the nucleus. In a nuclear change the elements can change from one to another. This is what happens when a nucleus emits particles and energy and a new element is formed. So the type of change occurring is a nuclear change.
Answer: d. a nuclear change.