The answer is B. Three days
Cultural diffusion is when groups are divided over time due to differences of opinions over time. One example for today would be the presidential election which divides many cultural groups because of the issues which each individual in the group supports.
I believe the correct answer is the final option -
He used a background of simple Classical columns and arches that don't detract from the figures.
If you take a look at the painting, you will see that you cannot learn much about history because you don't know what is going on, so A is incorrect. B is also incorrect because the colors don't detract from the story. C is incorrect because we don't know if that is true. D is the correct answer because you can see in the painting that the columns are in the background, just to provide a nice view.
Answer is: checks and balances.
Checks and balances were principles of separation of powers (shared powers) the founders added a system. Checks and balances enable that each branch of government (executive, legislative, <span>judicial</span>) exercises some control over the others branches.