Final answer:
Travel became more affordable for the average person during the Industrial Revolution, with advancements in technology, especially the railway system, making transportation cheaper and more accessible.
Step-by-step explanation:
The period in which travel became more affordable for the average person was during the Industrial Revolution. This era, which began in the late 18th century and continued into the 19th century, saw revolutionary advancements in technology and infrastructure. The advent of the railway made long-distance travel accessible and affordable, leading to the burgeoning of the middle-class population taking vacations and experiencing travel for leisure rather than necessity. Crucial to this change was the net effect of innovations in transportation, notably the railway system which made travel vastly cheaper, simpler, and faster than ever before in human history.
Therefore, the correct answer to the question is: B. Industrial Revolution.