What facts are required in order to conclude that m∠ade = m∠abc?

a)ad = db and ae = ec
b) ab = de and ac = bc
c) de = 2 •(bc), ad = 2 •(ab), and ae = 2 •(ac)
d) the exterior angle of a triangle is equal to the sum of the two remote interior angles.

Answer asap. you begin with 1/2 scoop of ice cream. since you're hungry, you ask the vendor for 2/7 more scoops of ice cream. then, you eat 5/8 scoops. how many scoops of ice cream are left on your cone? i will mark brainliest for first correct answer.