What happens/is likely to happen if the atoms within an element have full valence shells?

Question

$\begin{array}{1 1} \text{a. They are likely to bond with other elements more easily} \\ \text{ b. They are unlikely to bond with other elements.} \\ \text{ c. They will be labelled as unstable} \\ \text{d. They will explode} \end{array}$