Analogy: Signal is to Traffic as Lens is to ____. Identify what the second item regulates or controls, mirroring the first pair.

Introduction / Context:
A traffic signal regulates traffic flow. We need an object paired with what it regulates in the same manner.

Given Data / Assumptions:

• Signal → controls traffic.
• Lens → focuses/controls what?

Concept / Approach:
A lens refracts and focuses light, effectively controlling its path/convergence—a direct analogue to “signal controlling traffic.”

Step-by-Step Solution:
Map “controller → controlled flow.”Pick “Lens : Light.”

Verification / Alternative check:
Other options invert relations or pair unlike entities (e.g., dam : river is controller : controlled, but the format offered is “Dam : River,” not “Lens : Light” competitors).

Why Other Options Are Wrong:
Door : house is containment/access relation; operation : doctor inverts agency.

Common Pitfalls:
Overlooking that the second term must be the controlled medium.

Final Answer:
Lens : Light.