Which of the following statements are true $($as always, in general$)?$ For wrong ticks negative marks are given.

Which of the following statements are true $($as always, in general$)?$ For wrong ticks negative marks are given.

Every dag has a topological sorting.

A dag is undirected.

A dag has no cycles.

A dag is acyclic, and thus has cycles.

If a digraph is not a dag, then it does not have a topological sorting.

An arbitrary graph can be turned into a dag, by orienting the edges appropriately in one of the two possible directions.

A dag is connected.

There are dags with at least one vertex, where every vertex has incoming arcs.