Refer to graph G$1$ from the uploaded reference graphs here.

Consider running Dijkstra's shortest path algorithm upon graph G$1$ from source vertex $1.$ It may be useful for you to refer to the pseudo$-$code for Dijkstra's algorithm here.

In the main while$-$loop in which the Extract$-$Min operation takes place, we know that source vertex $1$ will be the first to be extracted from the root of the heap $Q.$

Which of the following is the fourth vertex to be extracted from the root of the heap?

Select one:

a$.4$

b$.5$

c$.2$

d$.3$

e$.6$Graph G$1$ is as follows:

Graph G$2$ is as follows.