There are 7 stores in town that had a total of 21 visitors on a particular day. However, only 11 people went shopping that day; some people visited more than one store. If 7 people visited exactly two stores each, and everyone visited at least one store, what is the largest number of stores anyone could have visited?
Choose the correct answer
A) 6 B) 8 C) 4 D) 9 E) 2

Rationale: "7 people visited 2 stores each for 14 visits . to maximize the number of stores that one person visited , let ' s assume that 3 people visited 1 store each . the number of remaining visits is 21 - 14 - 3 = 4 , which is the maximum that one person could have visited . the answer is c ."
Answer: C