Respuesta :
it's to show an exception (which is often the purpose of "yet") because in the first clause it identifies an action, then then it's like "but wait, maybe the action didn't really get going" in the second half of the sentence
The function of the transition "yet" in the sentence is to show an exception. (Option 3)
"Yet" as a conjunction is used as a way to show contrast or to present information that is surprisingly different from the information that was presented before. In this case, the information preceding "yet" was that there were plans for a railroad long before the Civil War. After the conjunction, the information contrasts with "the plans" by saying that officials did not agree on where to have the railroad.