The valency of noble gases is generally:

The general configuration of the noble gas family is given as ns²np⁶ except helium which has 1s².

Helium has one shell (k) which requires two electrons and helium has two-electrons so the outermost shell is filled and helium has no need to lose electrons or gain electrons. Therefore the valency of helium is taken as zero.

Similarly, every noble gas consisting of its outermost shell is completely filled and they are stable hence they don’t lose or gain any electron. Hence Valency of noble gases is zero.

Final Answer : Hence correct answer is A) Zero..