Which statement about perfect cubes is true?
a:25 is a perfect cube because 25 = 5 + 5 + 5 + 5 + 5
30 is a perfect cube because 30 = 3 times 10
512 is a perfect cube because 512 = 8 times 8 times 8
1,875 is a perfect cube because 1,875=25 times 25 times 3