Let's break this down. We know that group one metals are eager to donate an electron, and group 17 "halogens" are eager to accept an electron. They are very likely to bond, so we can eliminate option 1. Option two implies that they both want to keep the electron in their orbital, meaning option 2 two is out. A metalloid is an element that has metal and nonmetal properties, which means option 4 cannot be correct. Option three says that they will form an ionic bond, which is the kind of bond that forms between a metal and nonmetal. The answer is option 3.