The term marginal is used frequently in economics to refer to small incremental adjustments made on an existing plan of action. The term “margin” means “edge,” so marginal changes are adjustments made to add to the total (the amount at the edge) achieved thus far. Eating one more meatball at dinner (increasing the total number of meatballs eaten from 3 to 4), or drinking one more cup of tea at breakfast (increasing the total cups drunk from 2 to 3) are examples of marginal additions. As can be understood from the examples given the correct answer is “B”.