Let \( R \) be a relation defined on \(\mathbb{N}\) as \( a \, R \, b \) if \( 2a + 3b \) is multiple of \( 5 \), \( a, b \in \)\(\mathbb{N}\) . Then \( R \) is:
An equivalence relation
Not reflexive
Symmetric but not transitive
Transitive but not symmetric