For \( \alpha \in \mathbb{N} \), consider a relation \( R \) on \( \mathbb{N} \) given by \( R=\{(x,y)\}: 3x+\alpha y \text{ is a multiple of } 7\} \). The relation \( R \) is an equivalence relation if and only if:
\( \alpha = 14 \)
\( \alpha \) is a multiple of \( 4 \)
\( 4 \) is the remainder when \( \alpha \) is divided by \( 10 \)
\( 4 \) is the remainder when \( \alpha \) is divided by \( 7 \)
