The Theory of Modernisation and decay is formulated by

Modernization theory generally deals with how societies develop and become "modern".
Political decay refers to the decline of political institutions and order, often associated with instability and violence.

Samuel Huntington, a prominent political scientist, linked these concepts in his book "Political Order in Changing Societies".
He argued that rapid modernization, especially in developing countries, can outpace the development of strong political institutions.
This imbalance can lead to political decay, as the existing institutions struggle to cope with new demands and pressures.

Therefore, the connection between modernization and decay is most strongly associated with Huntington's theory.

While the other options are important figures in political science, their work is not primarily focused on this specific theory:
Rostow is famous for his stages of economic growth.
Pye contributed to the study of political culture and development.
Lipset explored the relationship between economic development and democracy.