The correct answer is: a) they are happy and stable because of the octet rule.
Noble gases, which include helium, neon, argon, krypton, xenon, and radon, are known for their lack of reactivity. This unique characteristic stems from their electron configuration. According to the octet rule, elements tend to bond in such a way that they achieve a full valence shell of electrons, typically eight electrons for the main group elements. Noble gases already have this complete valence shell, making them very stable and ‘happy’ in their elemental form.
In contrast, options b and c are inaccurate. Noble gases are not always trying to bond together; rather, their electron configuration leads them to avoid forming bonds with other elements. Additionally, they are not unstable; instead, their stability is what makes them ‘noble’ in chemical terms. Therefore, the noble gases remain largely inert, which is a significant aspect of their chemistry.