Answer:
The correct option is a) helium
Step-by-step explanation:
Noble gases can be described as the elements which belong to group 18 of the periodic table. The noble gases are unreactive as they have the correct number of electrons in their valence shells. This means that their arrangement of electrons is stable hence, the elements of this group are considered to be stable.
Among the options mentioned in the question, Helium is the element which belongs to the noble gases group. Hence, option A is correct.