Explanation:

Solution: 1

The correct answer is Option 1

An active sentence in the Present Continuous tense follows the order:

S + is/am/are + V1 + ing + O

And the passive sentence follows the order:

 O + is/am/are + being + V3 + by + S

In the above sentence, we find being and sought (V3 form) this shows that the given sentence is in the passive form. 

The passive sentence subject 'fair resolution' in the active form becomes the object

And the union members the object of the passive sentence becomes the subject

The verb being sought in the active form becomes are seeking.

Hence we get the sentence The union members are seeking a fair resolution to the problem.

Thus Option 1 is the correct answer.