What does this sign indicate?

A)No through traffic.
B)No entry.
C)Prohibition to pass without stopping.Correct
The sign in the question indicates the place where stopping is mandatory due to the proximity, according to the inscription it contains, of a customs post, police post, toll booth, or other. In any case, the driver who has stopped may not resume driving until having complied with the requirement established by the sign.
Do not confuse with the "no through traffic" sign or the "no entry" sign.