Which tempo marking indicates a speed that is slower than allegretto?

The choice of "Adagio" as the tempo marking that indicates a speed slower than "Allegretto" is correct because "Adagio" is defined as a slow tempo, typically ranging from 66 to 76 beats per minute. It is generally understood to convey a sense of calmness and expressive lyricism.

In contrast, "Allegretto" is often perceived as moderately fast, but slower than "Allegro," which is a faster tempo. Tempo markings in music are specifically categorized by their relative speeds, and "Adagio" is consistently placed lower on the tempo scale compared to "Allegretto."

Understanding these tempo terms is essential for musicians to interpret and perform pieces accurately, as they provide critical information about the intended speed and character of the music.