The correct option is A Both Statement and Explanation are correct and Explanation is the correct explanation for Statement.
The square of the wave function (ψ2) gives the probability density.
Since, ψ∝e−Zr2a0
ψ2∝(e−Zr2a0)2
At the nucleus, r=0
Hence, ψ2∝e−0∝1.
Thus, an s-orbital in H-atom corresponds to a non-zero probability density at nucleus.
Both Statement and Explanation are correct and Explanation is the correct explanation for Statement.