Well, by stating a, "typical" person, then the person eats 3 meals a day. A week is 7 days.
3*7=21 meals a typical person eats a week.
Now, common sense...
Is the number 21 in the thousands? No
Tens? Yes, yet there may be a better answer.
Ones? Agh no
Hundreds? No
All but one was a no which was... B. Tens