Which Terms Must Appear in the Unstated Premise of the Following

Which terms must appear in the unstated premise of the following argument? All days of the week are days that end in "y." Therefore, tomorrow is a day that ends in "y."

A) days of the week and days that end in "y"
B) tomorrow and days that end in "y"
C) tomorrow and days of the week
D) days of the week, days that end in "y," and tomorrow
E) There isn't enough information to be sure.