There are some people living on the island of lies. Half of them only tell lies on Wednesday, Friday and Saturday. The other half only tell lies on Tuesday, Thursday and Sunday. One day, all of the people living on the island said that they would tell the truth the next day. What day of the week was that day? 
选项为:A:Tuesday  B:Wednesday  C:Friday  D:Saturday  E:Sunday  请回答其中一个选项.