Answer:
Perfect, 3rd person, Passive, plural, neuter
Explanation:
The verb here (est) is in the perfect. Otherwise, it would be erat.
This eliminates the last two options.
All options list 3rd person, so that's of limited interest here.
Passive singular is not real, and even if it were, that option is already disproven by virtue of the verb form of est.
The word 'ducibus', which soluta is modifying, is neuter. The word declension also shows it is plural, eliminating the second option.
The first option—Perfect, 3rd person, Passive, plural, neuter—is the only answer which remains.
