Answer:
Wait what exactly we are supposed to do
<span>It was on such an island in the third summer of its yellow green that we built our watch fire. Not in the thicket of dancing willow wands, but on the level terrace of fine sand which has been added that spring a little new bit of world beautifully ridged with ripple marks and strewn with the tiny skeletons of turtles and fish all as white and dry as if they had been expertly cured. We had been careful not to mar the freshness of the place although we often swam to it on summer evenings and lay on the sand to rest.</span>
wrong ; matching ( for apex)
B) Gleefully.
Jubilantly is a positive emotion, extreme happiness and excitement. Gleefully is also an accurate description of that. Thus, gleefully is the best answer.
Hope this helps!