Solution:
The function is defined for \( x > 1 \) but excludes natural numbers \( \mathbb{N} \) from the domain due to the square root denominator constraint.
Since \( A \cap B = (1, \infty) - \mathbb{N} \), (S1) is true.
For (S2), \( A \cup B \) does not cover all real values in \( (1, \infty) \), making (S2) false.
Final Answer: (A) Only (S1) is true.