What is the tempo definition of larghetto in music?

The term "larghetto" denotes a tempo that is fairly slow but slightly faster than "largo." Larghetto is commonly understood to suggest a relaxed pace that allows for expressive interpretations while maintaining a flowing feel that isn’t as drawn out as largo. This makes option B accurate, as it effectively captures the essence of larghetto as a tempo marking that is slower than more rapid tempos but not the slowest one in the standard tempo hierarchy. The context of music often uses these terms to guide performers in achieving the desired emotional and rhythmic quality in their interpretations.

In contrast, the other options, while referencing various tempo ranges, do not appropriately align with the definition of larghetto. For instance, describing it as "fairly fast" or "moderately quick" does not fit the characteristic slowness of larghetto, and indicating it as "very slow" or akin to grave misrepresents its position in the broader range of tempo markings. Thus, the accurate identification of larghetto as fairly slow, but not as slow as largo solidifies the rationale behind choosing option B.