Which of the following four main limits of population growth is the one most easily controlled?
a. famine
b. birth control
c. disease
d. war

Birth control is the most easily controlled population growth factor as it can easily be handled through contraceptives and is affordable to do on an individual level, however Famine disease and war needs large scale measures to prevent.

Explanation:

The Best of option is "B"

birth control

Explanation:

population control movement, which aims to solve social and economic problems through fertility control. Population control moved through three stages: from the cause of "voluntary motherhood" to advance suffrage and women's political and social status, to the concept of "birth control" promoted by socialist feminists to help empower women and the working class.