this is the wrong answer. I want to understand what is the correct answer and why?

Figure: Shifting Demand Price $100 80 60 40 D2 D1 20 0 20 40 60 80 100 Quantity In the diagram, which of the following factors would cause the demand curve to shift from Dj to Dy? O a decrease in the price of a complement good O an increase in income if this is an inferior good O an increase in the population O an increase in the price of a substitute good Revealed