Answer:
D. 12, 6, 7
Step-by-step explanation:
For the triangle to have non-zero area, the sum of the shortest two sides must exceed the longest side.
A: 3 + 7 = 10 . . . . triangle has zero area
B: 4 + 5 < 10 . . . . sides don't meet
C: 6 + 8 = 14 . . . . triangle has zero area
D: 6 + 7 > 12 . . . . these form a triangle with non-zero area.
