Final answer:
A Business route sign indicates an officially designated highway that branches off the main highway and leads through the business section of the city, helping drivers find services and ensuring proper navigation and safety.
Step-by-step explanation:
When trying to determine the type of sign that indicates an officially designated highway which branches off the regularly numbered highway and leads through the business portion of the city, the correct option is an Business route sign. These signs are typically marked with a specific designation that includes the word 'Business' along with a number, which often complements the number of the main highway from which the business route deviates. These signs serve to guide motorists to a city's commercial center, where services such as food, lodging, and fuel may be available.
The importance of road signs extends to ensuring safety and informing drivers about distances, directions, and local routes. They are an essential part of road navigation and traffic management. Knowledge of these signs is crucial, especially when navigating new or unfamiliar routes.