Which of the following horse colors would be characterized by a yellow or gold body?

The horse color characterized by a yellow or gold body is indeed dun. This color typically features a body that can range from a light yellow to a deep gold shade, often accompanied by a darker mane and tail, as well as darker markings on the legs and face. Duns also have a distinct dorsal stripe running down their back, which is one of their defining features. The yellow or gold coloration in duns comes from the presence of the dun gene, which modifies the base coat color to create this unique appearance.

In contrast, sorrel is a reddish-brown color, chestnut refers to a range of reddish tones that can vary from light to dark, and blue roan describes a horse that has a mixture of white and black hairs, creating a bluish appearance. None of these colors embodies the yellow or gold tone associated with the dun. Thus, dun is the correct choice for this question.