You are driving on a road with one lane in each direction. Which roadsign indicates that you must always give way to oncoming traffic?

The two correct signs (1 and 2) both indicate that you must give way to oncoming traffic, but they do it in different ways:

Sign 1 (triangular with a narrowing road on the right) warns you that the road narrows on your side and that you must yield to oncoming traffic, which has priority because your lane is restricted.

Sign 2 (circular with a red border and arrows) explicitly shows that you must give way to oncoming vehicles. The red arrow points upwards (your direction) and the black arrow downwards (oncoming traffic), meaning you must let them pass first.

Sign 3 (triangular with two arrows, black pointing up and red pointing down) is a warning sign about two-way traffic, but it does not mean you have to give way to oncoming vehicles — it simply warns that traffic flows in both directions.

In summary, only signs 1 and 2 indicate an obligation to yield to oncoming traffic, as per German traffic regulations. Sign 1 warns about a narrow lane where you must yield, and sign 2 explicitly orders you to give way. Sign 3 just warns about two-way traffic without an obligation to give way.