Final answer:
During the Utah War, Johnston's Army was delayed by raiders, Salt Lake City was evacuated, and Fort Bridger was burned down, but thousands of innocent people did not die, which makes option d) the correct answer as the event that did NOT happen.
Step-by-step explanation:
The Utah War, also known as the Utah Expedition, occurred in 1857-1858 and involved confrontations between the Mormon settlers in the Utah Territory and the United States government. During this conflict, Johnston's Army was indeed delayed by raiders, and Salt Lake City was evacuated by the Mormon settlers as a precaution. Additionally, Fort Bridger was burned by the retreating Mormons so it would not be of use to the approaching U.S. Army.
However, d) Thousands of innocent people died did not happen during the Utah War. This option is incorrect because the conflict was relatively bloodless, with very few casualties reported on either side, certainly not reaching into the thousands.