Answer: d
Step-by-step explanation:
you can eliminate b and c off the bat because nobles are richer and more powerful than merchants. they're usually active in civil office, bureaucracy, or the imperial courts.
next, you can eliminate a because merchants were somewhat respected. their job required them to travel to other cities and even other countries, and they exchanged cultures, silk, hand-made jewelry, and dyes among other luxurious goods. therefore, they are higher than farmers. farmers were mostly peasants, working in tough conditions with low profits.