Let S= (a, b) a, b Z . Let R be the equivalence relation on S defined by (a, b) R(c, d) if a^2+b^2=c^2+d^2 . For (a, b) S let F(a, b) denote the equivalence class (c, d) S (a, b) R(c, d) of (a, b) . Then

Options

1. Athere exists (a, b) S such that F(a, b) has only one element.
2. Bthere exists (a, b) S such that F(a, b) has exactly 4 elements.
3. Cthere exists (a, b) S such that F(a, b) has exactly 6 elements.
4. Dthere exists (a, b) S such that F(a, b) has infinitely many elements.