Let \( N \) be the set natural numbers and a relation \( R \) on \( N \) be defined by \( R=\{(x,y)\in N\times N: x^{3}-3x^{2}y-xy^{2}+3y^{3}=0\} \). Then the relation \( R \) is:
Reflexive but neither symmetric nor transitive
An equivalence relation
Reflexive and symmetric, but not transitive
Symmetric but neither reflexive nor transitive