Explanation:

All of the above are correct.
First is correct. Due to the earth’s rotation, winds do not cross the isobars at right angles as the pressure gradient force directs, but get deflected from their original path. This deviation is the result of the earth’s rotation and is called the Coriolis Effect or Coriolis force. It is to the right in northern hemisphere and to the left in southern hemisphere.

Second is correct. The irregularities of the earth’s surface offer resistance to the wind motion in the form of friction. This force determines the angle at which air will flow across the isobars, as well as the speed at which it will move. It may also alter wind direction. For example, over the relatively smooth ocean surface, the friction is minimum, so the air moves at low angles to the isobars and at a greater speed.
Third is correct wind direction follows the direction of change of pressure, i.e. perpendicular to the isobars.
The differences in atmospheric pressure produce pressure gradient force. The rate of change of pressure with respect to distance is the pressure gradient. Pressure Gradient Force operates from the high pressure area to a low pressure area and causes wind movement.
The pressure gradient is strong where the isobars are close to each other and is weak where the isobars are apart.
Since a closely spaced gradient implies a steep pressure change, it also indicates a strong wind speed.