Diamond Ring is a phenomenon observed:
A. At the start of a total solar eclipse
B. At the end of total solar eclipse
C. Only along the peripheral regions of the totality trail
D. Only in the central regions of the totality trail

Hint: The diamond ring phenomenon is the feature of the total and the annular solar eclipses. A solar eclipse occurs when the Moon blocks the light of the sun from reaching to the Earth and it occurs when the Sun, the Moon and the Earth are aligned.

Complete step by step answer:
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.

Hence, from the given multiple choices- the option C is the correct answer.

Note:The diamond ring effect is also known as the Baily’s beads effect. The effect was named after an English Astronomer Francis Baily who explained the phenomenon in the year 1836.