The Central Difference Between the Structural Stagnation Hypothesis and the Secular

The central difference between the structural stagnation hypothesis and the secular stagnation theory is that:

A) structural stagnation applied in the 1940s and secular stagnation applies today.
B) structural stagnation focuses on declining investment while secular stagnation focuses on globalization.
C) structural stagnation focuses on globalization while secular stagnation focuses on declining investment.
D) structural stagnation is a hypothesis while secular stagnation is theory.