Translation:The lawyer's opinion is equivalent to the judge's opinion.
It's an awkward sentence in English, but I think that parallel is the best fit, besides matching the geometric meaning of מקבילה. You don't usually speak of opinions being parallel, but lines of thinking certain can be. The point is that the lawyer and the judge are thinking similar thoughts, and reaching similar conclusions.
Equivalent is just plain wrong. Opinions can be similar or even identical, but not equivalent.
The drop-down clue currently gives both equivalent and parallel. Either way I'm not crazy about the sentence. You might have a sentence, "The lawyer's opinion is in line with (or aligns with) the judge's opinion." Maybe that's what they were thinking when they created this sentence.