The Conventional Demand Curve Appears Strange to Many Students Since

The conventional demand curve appears strange to many students since the dependent variable (quantity) is on the vertical axis and the independent variable (price) is on the horizontal axis. We generally describe our demand as "If apples cost $1, then I'd be willing to buy four apples" instead of "If I want four apples, then I'd be willing to pay $1 per apple." Which concept reframes the dependent and independent variables so the orientation is more intuitive?

A) diminishing marginal utility
B) indifference curve
C) budget constraint
D) marginal rate of substitution