The correct answers are
a. are fluffy
d. form 1–1.5 miles above Earth
e. can extend up to 10 miles into the sky
Reason -
Cumulus clouds are puffy clouds which resembles a floating cotton. These clouds starts forming above the ground at a height of 1000 meters (nearly equals to 1–1.5 miles above Earth) . These are also known as thunderstorm clouds which grows vertically and have their top extending upto a height of 12000 m (7 to 8 miles)