Answer:
I think the correct answer is B
Explanation:
It seems like that's the only one that would make sense other than maybe D. And if I'm wrong I apologize, hope I helped.
I would say horse or letter but i could be wrong
Adding -s is the most common. for example: books, cups, pencils, etc. -es might have been the one that confused you, but that isn't a super common ending for plurals--instead, a more common one would be "-ies" which is when you drop the y (berry becomes berries, for example).
I believe it's A, Everyone who wants to succeed in life needs to manage his or her money. B,C, and D doesn't have any errors.
Hope this helps!