Final answer:
The sentence regarding the completion of the first transcontinental railroad is grammatically correct as originally written, with no change needed to the placement of the comma after 'ACT'. Moreover, the actual location of the golden spike ceremony was Promontory Point, Utah.
Step-by-step explanation:
The completion of the first transcontinental railroad in the United States was a monumental event in the nation's history. When discussing the grammar in the provided sentence, the correct action is to replace the comma after the year 1869 with a semicolon.
The sentence would then read: "In May 1869; seven years after President Lincoln had signed the Pacific Railway Act, the final spike for the track was hammered into place in Promontory Point, Oregon."
However, this is an error, as the original placement of the comma is correct and should not be replaced with a semicolon.
Also, it is essential to correct the mistake regarding the location, as the golden spike was driven in Promontory Point, Utah, not Oregon. Therefore, the correct answer to the question is option 3, no change.