Thomas Hobbes’s philosophical tract Leviathan was first published in

The correct option is 1651.

Thomas Hobbes’s pioneering work of political philosophy, Leviathan, was first published in the year 1651.
The treatise was written during the tumultuous period of the English Civil War (1642–1651). In Leviathan, Hobbes presents his theory of the social contract, arguing that peace and social unity can best be achieved through the establishment of a strong, undivided sovereign authority to rule over society and prevent the state of nature, which he famously described as a state of constant war of all against all.