Are the 6-inch hot dogs made entirely of beef?

The statement that the 6-inch hot dogs are made entirely of beef is correct because Sonic's standard hot dogs are marketed as being made with 100% beef. This specificity emphasizes the quality and type of meat used, appealing to customers who prefer a beef-only option.

While there may be variations or promotions that involve different types of hot dogs or toppings, the basic product, which is the 6-inch hot dog, is fundamentally beef-based. This makes the answer appropriate and aligns with the representation of Sonic's menu items focused on beef hot dogs.

The other options concern nuances in the product offering or conditions that do not apply to the standard 6-inch hot dogs, reinforcing the clarity of Sonic's brand consistency in their hot dog offerings.