Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.

[EX Q]: Problem: the average age of a family of 5 members is 20 years. if the age of the youngest member be 10 years then what was the average age of the family at the time of the birth of the youngest member ?
Options: a. 13.5, b. 14, c. 15, d. 12.5, e. none
[EX A]: d

[EX Q]: Problem: what is the normal price of an article sold at $ 72 after two successive discounts of 10 % and 20 % ?
Options: a. $ 92, b. $ 96, c. $ 100, d. $ 104, e. $ 108
[EX A]: c

[EX Q]: Problem: there are 9 baskets numbered from 1 to 9 and filled with apples. 10 children are asked to pick apples one by one from each basket such that the number of apples picked by each child from each basket is equal to the number marked on the basket. if there were 1000 apples in total and the baskets were filled in such a way that none of the basket became empty in the process, how many apples were left in the end ?
Options: a. 440, b. 550, c. 660, d. 770, e. 880
[EX A]:
b