Explanation:

- Cities and Directions:

- City U is 9 km east of City V.

- City W is 5 km south of City U.

- City X is 3 km west of City W.

- City Y is 5 km north of City X.

- City Z is 7 km south of City X.

- Check Linearity:

- Option 1: XZY

- City X, City Z, and City Y are vertically aligned.

- ?? (This is the correct option)

- Option 2: UVW

- V-U is east, U-W is south, forming a right angle, not a line.

- Option 3: YWU

- Y is north, W is south, U is east, forming angles with no straight path.

- Option 4: UXZ

- U is east, X is west and Z is even more south, forming a zigzag path.