In this question, Statement I states that geostrophic wind blows above a height of 600 meters, parallel to the isobars. This means that the wind at this height moves parallel to the lines on a map that connect points of equal pressure, known as isobars.

Statement II explains that geostrophic wind is the horizontal wind velocity in which the Coriolis force balances the horizontal pressure force. The Coriolis force is a deflecting force caused by the rotation of the Earth, which affects the wind direction. The horizontal pressure force refers to the force exerted by differences in air pressure.

Option 1 states that both the statements are individually true, and statement II is the correct explanation of statement I. This is the correct answer because the geostrophic wind does flow parallel to the isobars, and this is due to the balancing of the Coriolis force and the horizontal pressure force. Therefore, statement II provides the correct explanation for statement I.

The other options are incorrect. Option 2 states that both the statements are individually true, but statement II is not the correct explanation of statement I, which is not true. Option 3 states that statement I is true and statement II is false, which is not accurate based on the correct explanation