What is the meaning of the following traffic sign?

1. Correct answer: Begining of traffic restriction zone.
2. The minimum permitted speed is 30 k.p.h.
3. Beginning of 30 k.p.h zone.
4. The maximum permitted speed is 30 k.p.h.

WhyThis sign marks the beginning of a speed-restricted zone; the stated limit applies inside it. A minimum speed is not shown this way.