a) Given above is the utility function for such preference, the utility is increasing in the direction of the arrow, Robin is neutral for material goods and more horse ride makes him better off.
b) Monotonic preferences mean more of a good is preferred to less, here Robin is indifferent to the quantity of material good but prefers more of the horse ride, any increase in the quantity of material good, will not increase the utility of Robin, hence the preferences are not monotonic.
c) Convex preference means that averages are preferred to extremes, which implies that the consumer prefers to consume both the goods rather than any one, but here Robin is only concerned about the horse ride, therefore, his preference is not convex.
3. Robin's Preferences Robin is an ambitious young knight living in the middle ages. He is...