Consider the following pseudocode for depth-first search (DFS) algorithm which takes a directed graph $G(V, E)$ as input, where $d[v]$ and $f[v]$ are the discovery time and finishing time, respectively, of the vertex $v \in V$.

Suppose that the input directed graph $G(V, E)$ is a directed acyclic graph (DAG). For an edge $(u, v) \in E$, which of the following options will NEVER be correct?

An undirected, unweighted, simple graph $G(V, E)$ is said to be 2 -colorable if there exists a function $c: V \rightarrow\{0,1\}$ such that for every $(u, v) \in E, c(u) \neq c(v)$.

Which of the following statements about 2-colorable graphs is/are true?

Consider the following algorithm someAlgo that takes an undirected graph $G$ as input. someAlgo ( $G$ )

1. Let $v$ be any vertex in $G$. Run BFS on $G$ starting at $v$. Let $u$ be a vertex in $G$ at maximum distance from $v$ as given by the BFS.

2. Run BFS on $G$ again with $u$ as the starting vertex. Let $z$ be the vertex at maximum distance from $u$ as given by the BFS.

3. Output the distance between $u$ and $z$ in $G$.

The output of someAlgo( $T$ ) for the tree shown in the given figure is $\qquad$ . (Answer in integer)

Let $G(V, E)$ be an undirected and unweighted graph with 100 vertices. Let $d(u, v)$ denote the number of edges in a shortest path between vertices $u$ and $v$ in $V$. Let the maximum value of $d(u, v), u, v \in V$ such that $u \neq v$, be 30 . Let $T$ be any breadth-first-search tree of $G$. Which ONE of the given options is CORRECT for every such graph $G$ ?