Answer is A. 24, 24, and 47
This deals with the Triangle inequality theorem. It basically says that the two shortest sides, when added together, must be greater than the longest side.
A. 24 + 24 = 48 48 > 47
B. 15 + 30 = 45 45 = 45
C. 23 + 28 = 51 51 < 55
D. 8 +17 = 25 25 = 25