The vector equation of the line joining the points $\mathbf{i}-2 \mathbf{j}+\mathbf{k}$ and $-2 \mathbf{j}+3 \mathbf{k}$ is
(a) $\mathbf{r}=t(\mathbf{i}+\mathbf{j}+\mathbf{k})$
(b) $\mathbf{r}=t_1(\mathbf{i}-2 \mathbf{j}+\mathbf{k})+t_2(3 \mathbf{k}-2 \mathbf{j})$
(c) $\mathbf{r}=(\mathbf{i}-2 \mathbf{j}+\mathbf{k})+t(2 \mathbf{k}-\mathbf{i})$
(d) $\mathbf{r}=t(2 \mathbf{k}-\mathbf{i})$