Someone me do this question step by step ? asap

When y’all answer can y’all explain too !

Atriangle with all sides of equal length is a/an triangle. a. right b. scalene c. equilateral d. isosceles

How do i start to solve? would appreciate a walk-thru! a bird sitting 16ft above the ground in an apple tree dislodges an apple. after how many seconds does the apple land on the ground? (assuming that no branches will interfere with it's fall)