Answer: Option (a) is the correct answer.
Explanation:
It is known that elements which have completely filled octet when they are present in neutral state then they do not need to gain or lose an electron. Hence, the element becomes unreactive in nature.
For example, neon is a noble gas whose atomic number is 10 and its electronic distribution is 2, 8. As they have completely filled orbitals so they do not react with other elements.
As a result, they are rarely found in combination with other elements.
Thus, we can conclude that the Group 8A(18) elements are unreactive and are rarely found in combination with other elements.
