The number of the members of a club is more than 50 and less than 80. When 5 people sit at a table, other people exactly divided to 8-people groups (8 people sit at a table) or 7-people groups (7 people sit at a table). If the members are divided to 9-people groups, how many people will be left?  Select the correct option:
A) 4
B) 5
C) 6
D) 7
E) 8

Rationale: "the number of members is 7 k + 5 = 8 j + 5 the only number in this range which satisfies this is 61 . 61 / 9 = 6 ( 9 ) + 7 the answer is d ."
Answer: D