Since 1900 in the US, family income has greatly increased (even after accounting for inflation), but the average number of children per family has decreased. Illustrate each of the following possibilities using budget constraints and indifference curves. (a) Children are an inferior good. (b) Children are not an inferior good, but it has become more expensive to bear and raise them, relative to other goods. (c) Children are not an inferior good, and they have not become relatively more expensive. What has happened is that tastes have changed: couples want smaller families today.