What musical direction is indicated by "alla marcia"?

"Alla marcia" indicates a musical direction that means to perform in a march style. This style typically features a strong and regular beat, which is ideal for marching. The character of the music is often straightforward, dignified, and robust, intended to create a sense of forward motion that is characteristic of marching music.

In this context, the other options do not accurately reflect the essence of "alla marcia." While a march may be performed at a steady tempo, the defining feature is really about the style rather than merely the tempo alone. Similarly, the terms regarding the minim beat and varied tempo do not convey the specific character associated with a march. Thus, the emphasis on style in the correct answer encapsulates the meaning of this musical direction perfectly.