BFS starting from node $\text{'}$B$\text{'}$:

Initial Queue: $[$B$]$

Visit B$,$ enqueue neighbors $($in alphabetical order$)$: $[$G$,$ I$]$

Visit G$,$ enqueue neighbors: $[$I$,$ A$,$ E$]$

Visit I, enqueue neighbors: $[$A$,$ E$,$ C$]$

Visit A$,$ enqueue neighbors: $[$E$,$ C$]$

Visit E$,$ enqueue neighbors: $[$C$,$ H$]$

Visit C$,$ enqueue neighbors: $[$H$]$

Visit H$,$ queue is now empty.

Order of traversal: B$,$ G$,$ I, A$,$ E$,$ C$,$ H

illustrate how the queue changes step by step