What are key economic variables that economists use to predict a new phase of a business cycle referred to as?

The second fundamental theorem of welfare economics states that

A) under certain conditions, a competitive equilibrium is Pareto optimal. B) a competitive equilibrium is always Pareto optimal. C) under certain conditions, a Pareto optimum is a competitive equilibrium. D) a Pareto optimum is always a competitive equilibrium.

With regard to the Navigation Acts (1651 and later amendments), all of the following answers are true except

(a) No commodities originating from the Empire were to be shipped in any but British (including colonial) ships. (b) No commodities imported into the Empire were to be carried in any but British ships. (c) Only British subjects were allowed to be merchants in the colonies, and only British ships were to carry commodities from one English port to another. (d) There is no "except"; all of the above answers are true.