Final answer:
The ceremonial golden spike marking the completion of the first transcontinental railroad was driven at Promontory, Utah. The correct answer to the question is b) Utah.
Step-by-step explanation:
The so-called golden spike ceremony that marked the completion of the first transcontinental railroad was held in Utah. Hence, the correct option is b) Utah. On May 10, 1869, the golden spike was driven into the ground at Promontory, Utah, signaling the joining of the Union Pacific and Central Pacific railroads. This monumental event reduced travel time across America from months to just one week and sparked the subsequent construction of additional transcontinental railroads that further expanded the nation's connectivity.