Answer: number 4 (43º, 62º, 75º)
Explanation:
26 + 42 + 106 ≠ 180 so number 1 is not a triangle.
34 + 63 + 79 ≠ 180 so number 2 is not a triangle.
62 + 34 +80 ≠ 180 so number 3 is not a triangle.
43 + 62 + 75 = 180 so number 4 is a triangle.
Because only the angles are given and not the sides, there is an infinite number of triangles. The answer is number 4 (43º, 62º, 75º).