The correct answer is "Between 1800 and 1850. London's population more than doubled" (page 18)
Explanation:
"The Great Stink" is a text that describes the social, economical, and political conditions in London in the 19th century, especially during the period known as the Great Stink during which there was a sanitary crisis.
In this context, the section "Between 1800 and 1850. London's population more than doubled" supports the statement "The 19th century was a time of rapid change in London" because this statement explains how the social conditions evolved during a short time due to a rapid increase in the population. Considering this rapid growth had a great impact on other factors such as politics, economy, and even health.