$\mathbf{r}(t) = \langle 1+3t, 2-3t \rangle$

$\mathbf{r}(t) = \langle 4-3t, -1+3t \rangle$

$\mathbf{r}(t) = \langle 1+4t, 2-t \rangle$

$\mathbf{r}(t) = \langle 3t, -3t \rangle$