Explanation:

- Ultra High Frequency (UHF) waves are typically in the range of 300 MHz to 3 GHz.

- Option 1: Ground waves

- These waves follow the contour of the earth.

- They are most effective at lower frequencies, such as AM radio.

- Option 2: Sky waves

- These waves are reflected back to Earth by the ionosphere.

- They are effective for long-distance communication but not typically used in the UHF range.

- Option 3: Space waves

- UHF waves normally propagate by means of space waves.

- These travel in a straight line and are used in line-of-sight communication like TV broadcasts and mobile phones.

- Option 4: Surface waves

- Similar to ground waves, these hug the surface.

- They are not typically used for UHF frequencies.