The correct answer is option 3: the jet streams are narrow meandering bands of swift winds which blow in the midlatitudes near the tropopause and encircle the globe.

Let`s dissect each option to understand them better:

Option 1 states that the jet streams are wind systems with a pronounced seasonal reverse at a direction. However, this is not accurate. The jet streams do have seasonal variations, but they do not reverse their direction.

Option 2 suggests that the jet streams are winds blowing from the subtropical high-pressure belts towards the subpolar low-pressure belts. While this is partially true, it does not fully describe the jet streams. They are not solely restricted to blowing between specific pressure belts.

Option 3, which is the correct answer, states that the jet streams are narrow meandering bands of swift winds that blow in the midlatitudes near the tropopause and encircle the globe. This option accurately describes the jet streams and their characteristics.

Option 4 incorrectly proposes that the jet streams are winds blowing from the subpolar low-pressure belts towards the subtropical high-pressure belts. This is not a correct representation of the direction of the jet streams.

Therefore, the correct answer is option 3.