Which statement explains why the bonds between nonmetals tend to be covalent?

Lilpeeq's question is legitimate, but I'm going to try to answer without the statements anyway (potentially ill-advised, but here we go!). Nonmetal-nonmetal bonds are more likely to be covalent because their electronegativites are very similar. Ionic bonds form between elements with large differences in electronegativities, and the smaller the difference is, the more covalent the bond is until an element that bonds with itself forms a perfectly covalent bond. Metals form metallic bonds with each other.

EDIT: Basically they have small differences in electronegativity. Thanks for following up on your question!
Hope this helps!