Answer:
b. a strike-slip fault that forms the boundary between tectonic plates
Explanation:
Firstly, a strike-slip fault is simply an horizontal motion parallel to the strike of the faults surface.
A transform faults usually exist between tectonic plates boundaries and usually their is a strike-slip movement along the faults. The most notable transform faults is the San Andrea faults in California.
Generally, transforms faults comes from the fact that the displacement along the faults abruptly ends or transform into another kind of displacement.