Quiz: Hierholzer's Algorithm

Hierholzer's algorithm starts at a node and walks until returning to the start. If unvisited edges remain at some node $v$ on the circuit, what does it do next?

1. A.Start a new circuit from $v$ and append it to the end
2. B.Backtrack to the start and try a different first edge
3. C.Start a new circuit from $v$ and splice it into the existing circuit at $v$
4. D.Mark $v$ as a dead end and remove it from the graph