“That is incorrect. Try again. Seriously, try again”
How, exactly, is that incorrect? What do the words “earn” and “merit” even mean then? If a merit is something you possess which is worthy of reward, and, in the case of the catechism, is something that we have which can receive both early benefits and eternal rewards for possessing. And if to earn something is to be worthy to receive something due to possessing some merit, then, in either case, you are receiving grace as a debt (you are earning it) for your merits.
If not, then what is the definition of merit? Why is meriting being mentioned at all, if actually you receive nothing for your merits? And why did your link argue that salvation is a reward for good works, if your purpose was to deny that?
“How, exactly, is that incorrect?”
You don’t know? If you don’t, then how can you compare it to merit which only now you want me to define? This is the hubris of Protestant anti-Catholics on display.