Diamond Ring is a phenomenon observed

only along the peripheral regions of the totality trail.

The correct answer is Option (3) - only along the peripheral regions of the totality trail.

During the solar eclipse, as the Moon covers the Sun the rocky topography of the lunar limb allows only the beads of the sunlight to shine in some of the places and while not in other places. When the single bead is left, the diamond ring effect is seen and it appears as the shining “diamond” set in the bright ring around the lunar edge of the object. Therefore, the eclipsed Sun appears like the shining diamond ring and this phenomenon is known as the diamond ring phenomenon or the diamond ring effect. Therefore, Diamond Ring is a phenomenon observed only along the peripheral regions of the totality trail.