Answer: Option B
:
B
As (x,x) $ϵ$ R   $\Rightarrow$ $|x-x|\le$ 1
$\Rightarrow$ 0 $\le$ 1 (True),
Thus, reflexive.
As (x,y) $ϵ$ R   $\Rightarrow$  $|x-y|\le$ 1
$\Rightarrow |y-x||\le 1\Rightarrow$ (y,x) $ϵ$ R,
Thus, symmetric.
Again, (x, y) $ϵ$ R and (y, z) $ϵ$ R
$\Rightarrow |x-y|\le$ 1   and $|y-z|1\text{/}\Rightarrow |x-z|\le$ 1
$\therefore$ Not transitive