Data Sufficiency

Each Statement is clearly insufficient alone. Using both, if line two has a slope of 1, then line two would form a 45 degree angle where it meets any horizontal line. If lines one and two meet at a 40 degree angle, then line one either creates a 5 degree or an 85 degree angle with any horizontal line, but in either case line one would be rising as it moves to the right, so it must have a positive slope, and the answer is C.