This sign...
A)indicates how a truck must park.
B)prohibits parking if the truck is more than 10 metres long.
C)prohibits the passage of vehicles or combinations of vehicles with a maximum length, including the load, exceeding 10 metres.Correct
The sign in the question prohibits the passage of vehicles or combinations of vehicles whose maximum length, including the load, exceeds that indicated.
This sign applies to all vehicles regardless of their purpose.
Not to be confused with the width restriction sign: