If you are making a left turn, you must begin:

When making a left turn, it is essential to begin in the leftmost lane in the direction you are traveling. This practice is crucial for safety and proper road etiquette. By starting in the leftmost lane, you position your vehicle effectively to make a smooth turn without obstructing or interfering with other lanes of traffic.

Turning from the leftmost lane also helps to ensure that you are aligned correctly with oncoming traffic, allowing you to make the turn at the appropriate angle and reducing the risk of collisions. This approach is particularly important in busy intersections, where clear lanes can help maintain the flow of traffic and enhance the safety of all road users.

Other options would lead to potential hazards. Starting in the rightmost or center lanes could confuse other drivers and lead to dangerous maneuvers, particularly if there are no designated turn lanes for left turns. Meanwhile, beginning your turn "at the last available lane" could imply starting too late or even inappropriately navigating through traffic to make the turn, which is unsafe and against driving regulations.