What tempo should a piece marked "Adagio" be played at?

The term "Adagio" in music terminology is used to indicate a slow tempo, typically ranging from around 66 to 76 beats per minute. This tempo is characterized by a relaxed and leisurely pace, allowing for expressiveness and lyrical quality in the music. The option indicating "moderately slow" reflects a more nuanced understanding of the term, as "Adagio" suggests a slower tempo that is not as drawn out as "Lento," but not fast enough to be classified as "Allegro" or even at a walking pace.

In the context of the other answers, "very slow" might imply an even slower tempo that could be better associated with terms like "Largo" or "Grave." "Fast" stands in contrast to the characteristics of "Adagio," and "walking pace" suggests a speed that is considerably quicker than the slow, expressive nature of "Adagio." Thus, "moderately slow" captures the essence of "Adagio" best and aligns with how the term is typically interpreted in musical contexts.