Pls help me in math ion understand

How can firms use marginal analysis to determine the price of a product? a) profit maximization can occur when the marginal cost exceeds the marginal revenue. b) the total cost of production can determine the individual unit price of a product. c) marginal analysis can be used to determine at what price profit maximization occurs. d) firms can calculate the marginal cost of a product and set the price lower than the cost.

Love, which can’t be observed or measured directly, is an example of psychological construct

This is an ap world history question. i am working on a worksheet which has a vent diagram with each circle labeled either us or byzantine economy. the middle is the similarities. can someone explain to me the similarities and especially the differences between the two?