Which of the following signs prohibits traffic with a smaller space than the one shown on the sign?

Explanation
The red-bordered circle marked 70 m above two vehicle silhouettes requires that minimum following distance, so traffic with a smaller gap is prohibited. The 2.7 m circle with inward-pointing markers limits vehicle width, while the truck-and-10 m circle with outward-pointing markers limits vehicle length; neither controls the gap to a vehicle ahead.