Congrats! what do you think was the best thing you did to improve?

Hey me and a friend have been going over this question quite a bit. I understand how the first part of answer D is incorrect but I was also cautious of the word "inclination" being used. JY also circled "inclination" almost as if he was cautious of it too but didn't explain why. Can anyone explain why he might of done that and if the second half of answer choice D is also incorrect or completely true, or somewhere in between?