$R$ is the relation on $\mathbb{N}$ given by $a \mathrel{R} b$ if $a$ divides $b$. Which of these describes $R$?

Explanation

1. 01

   Every $a$ divides itself, and if $a \mid b$ and $b \mid c$ then $a \mid c$.

2. 02

   2 divides 4 but 4 does not divide 2, so it is not symmetric.