According to ACBA, which of the following is NOT a variety or color group for cavies?

The correct answer is that "Marking" is not recognized as a distinct variety or color group for cavies according to the American Cavy Breeders Association (ACBA).

In the context of cavy color groups, "Solid," "Agouti," and "Self" are valid classifications. Solid refers to the uniform coloration found throughout the cavy's coat, whereas Agouti relates to the specific patterns and coloration typically characterized by bands of color on each hair. Self describes cavies that are one solid color without any markings or patterns. These classifications are critical for determining breed standards and assessing cavies during shows.

Understanding these classifications helps breeders and exhibitors select and judge animals based on accepted standards. Since "Marking" does not fit into the recognized categories as defined by the ACBA, it stands out as the correct choice for this question, thus reinforcing the importance of familiarizing oneself with official breed standards in the realm of cavy showmanship.