Answer:
D - chemical and physical
Explanation:
Only chemical and physical changes can reach the level of dynamic equilibrium. Nuclear reactions cannot reach dynamic equilibrium. 
- A system is in dynamic equilibrium when the rate of forward reaction is the same as that of backward reaction in a reversible reaction. 
- Nuclear reactions cannot be reversed. 
- Dynamic equilibrium is prominent in chemical reactions. It is commonly found that as a reaction occurs, the backward and forward reactions can reach equilibrium levels. 
- In physical changes, this can also occur when certain conditions of pressure and temperatures are satisfied.