Final answer:
Road signs guide drivers on the proper actions at intersections. If in the right lane, vehicles must turn right at the next intersection unless a sign indicates differently.
Step-by-step explanation:
The correct interpretation of roadway signage is crucial for ensuring safety and compliance with traffic laws. If vehicles are driving in the right lane, they must turn right at the next intersection unless otherwise indicated by a sign. In this scenario, the correct action is letter D) "Turn right at the next intersection if in the right lane." Ignoring the sign and continuing straight is not an option since road signs are designed to direct traffic safely through intersections.