Answer:
A line a and line b
Explanation:
Lines b and c are parallel (no intersection points), so the system will have no solutions.
Lines b and d are parallel (no intersection points), so the system will have no solutions.
Lines c and d coincide (infinitely many intersection points), so the system will have infinitely many solutions.
Lines a and b will intersect after extension, so the system of these two equations will have only one solution.