Final answer:
The term that refers to the maximum axial load that can theoretically be applied to a column without causing it to buckle is the Critical load (d).
Step-by-step explanation:
The term that refers to the maximum axial load that can theoretically be applied to a column without causing it to buckle is the Critical load (d).
The critical load takes into account factors such as effective length and moment of inertia to determine the maximum load that can be applied before buckling occurs.
It is important to distinguish between the critical load and other terms such as ultimate load, safe load, and buckling load, as they represent different concepts related to the behavior of columns under load.