Quiz: Euler Tour Variants

You need to answer path sum queries (sum of values from root to node $v$). Which Euler tour variant should you use?

1. A.Entry-only variant, where each node appears once
2. B.Full tour variant, where edges are recorded as you traverse them
3. C.Any variant works. The choice does not matter
4. D.Entry-exit variant, with $+$value at entry and $-$value at exit