Pre-colonial Africans used a variety of materials to create musical instruments, with many instruments being made from natural resources readily available in their environments. Among the options provided, the most likely material that was commonly used is vegetable husks.
Vegetable husks and other plant materials were often used in the construction of instruments like drums, rattles, and string instruments. Sinew from animals (like gazelles) could also be used for strings in some instruments, but the option of vegetable husks aligns more broadly with traditional practices in creating a variety of musical instruments across various African cultures.
Bald eagle feathers and hollow copper spheres were not typically associated with African musical instrument construction in a traditional context.