If a production possibility curve is a straight line, it tells us that the opportunity cost of producing one more unit of good x

for one more unit of good x traded-off , an additional unit of good y can be produced.

Explanation: The production possibilities frontier is graphed as a curve with one of the commodities is shown on the x-axis, while the other is shown on the y-axis. The curve is made up of points at which the two commodities are being produced in different amounts, most efficiently using the limited resources that they require with keeping the production factor and technology the same for both commodities. A production possibility curve or frontier represents different values of two good that an economy can produce ,keeping the production factor and the technology constant .

The slope of production possibility curve shows the opportunity cost I.e how much of good y has to be given up in order to produce an extra unit of good x . If the production possibility curve is a straight line , it means that the slope is constant I.e to produce an extra unit of good x , there’s constant opportunity cost of good y to be given up .

d, conspicuous consumption is when you try to increase your wealth or social status (and in the case he's trying to create the perception of wealth considering he can't really afford it)