content area top Part 1 Find the set Upper A union Upper B. Upper U equals StartSet 1 comma 2 comma 3 comma 4 comma 5 comma 6 comma 7 EndSet Upper A equals StartSet 1 comma 2 comma 3 comma 5 EndSet Upper B equals StartSet 4 comma 2 comma 6 EndSet Question content area bottom Part 1 Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. Upper A union Upper B equalsStartSet nothing EndSet (Use a comma to separate answers as needed.) B. Upper A union Upper B is the empty set