On a one-way street, you may turn left onto another one-way street only if:

Answer: B — Traffic on the street moves to the left.

On a one-way street, you can turn left onto another one-way street only if the street you’re entering has traffic moving to the left. This keeps your turn in the same direction as the flow of traffic and avoids driving into vehicles coming toward you from the other direction. If the destination street’s traffic moves to the right, turning left would put you into oncoming traffic, which is unsafe and not allowed. A green arrow can provide a protected turn, but it’s not required; the essential rule is matching the traffic flow on the street you’re entering.