Let us consider an unweighted graph G . Let a breadth-first traverse of G be done from a node r . Let $\mathrm{d}(\mathrm{r}, \mathrm{u})$ and $\mathrm{d}(\mathrm{r}, \mathrm{v})$ be the lengths of the shortest paths from $r$ to $u$ and $v$ respectively, in G . of $u$ is visited before $v$ during the breadth-first traversal, which of the following statements is correct?
A. $d(r, u)<d(r, v)$
B. $d(r, u)>d(r, v)$
C. $\mathbf{d}(\mathbf{r}, \mathbf{u})<=\mathbf{d}(\mathbf{r}, \mathbf{v})$
D. None of the above