Answer:
A. Metallic bond
Explanation:
Think about it: copper and tin are both common metals. That's how we know it's a metallic bond!
Why not B: Covalent bonds are between two nonmetals.
Why not C: Ionic bonds are between a nonmetal and a metal.
Why not D: Paired bond isn't a common phrase in chemistry.
Cross-pollination is the transfer of pollen from the anther of one flower to the stigma of another flower on a different individual of the same species. Self-pollination occurs in flowers where the stamen and carpel mature at the same time, and are positioned so that the pollen can land on the flower's stigma.