What must you be prepared for when you pass these traffic signs?

Your answer is fully correct.

The triangular warning sign with an exclamation mark signals a general danger or hazard ahead. The additional plate showing a skier indicates that the road may be used for winter sports like skiing. This means you must expect winter sports activity on or near the road (option 1).

Also, this sign combination warns you to prepare for packed snow or black ice on the roadway (option 2), because winter sports usually take place on snow or icy conditions which can make driving dangerous.

Option 3 is not correct because the warning specifically applies to the road itself, not just the pavements.

In summary, when you see these signs, you should be prepared both for winter sports activity on the road and for hazardous road surface conditions like packed snow or black ice, which require careful and cautious driving.