Economic models

A. assume that all factors in the model change at the same time.

B. include every detail found in the real world.

C. are not tested using real-world data.

D. can be used to explain or predict economic phenomena.

D.

Explanation:

A economic model can be used to explain or predict economic phenomena, because every model has to have key variables that command the economic decisions and operations.

An economic model is define to get a specific goal, so when some problem comes, you can study every decision based on the model applied, that 'simplifies' solutions, or even better, you must be able to predict when economic problems will arrive.