When is an unprotected left turn authorized at an intersection?

Answer: B — Only with the appropriate sign, a green signal, and sufficient clearance

An unprotected left turn is authorized at an intersection under specific conditions to ensure safety and proper traffic flow. When there is a green signal present, it indicates that the traffic light allows for movement, and the appropriate signage signals that left turns can be made. Sufficient clearance is crucial as it ensures that the turn can be completed safely without interfering with oncoming traffic or crossing pedestrians. Making a left turn under the right conditions, where both timing (the green light) and signage support the turn, reduces the risk of accidents significantly. This practice is particularly enforced at busy intersections where both left-turning vehicles and oncoming traffic are present. Therefore, this answer encapsulates the safe protocol for executing an unprotected left turn amidst other road users.