Let's look at what both passages are saying. The author of Passage A argues that mixing music and words - as in opera or song - could produce "various good ends" but only if the words are subordinated to te more expressive medium of music (lines 13-16), concluding that the aesthetic value of an opera, therefore, depends on the accompanying music, rather than the plot or poetry/ words.
The author of Passage B talks about two types of operas - where music is primary and where there is parity between music and other factors and argues that in any aesthetic judgment of opera, music and poetry must be considered in a unified fashion.
Let's look at the answer choices: (A) Is music inherently a more expressive medium than poetry? Incorrect. The author of Passage B says we should not judge either in isolation, thus he is not trying to make a comparative judgment.
(B) Is the emotive power of poetry enhanced when it is set to music? Incorrect. The author of Passage B is not concerned with the emotive power of poetry.
(C) Should opera be accorded the same respect as other forms of classical music? Incorrect. Neither passage is concerned with comparing the level of respect for opera with other forms of music
(D) How important are words to the artistic effectiveness of opera? Correct. The author of Passage A considers the role of words in opera and concludes that its aesthetic value/ artistic effectiveness is largely derived from the musical element rather than the plot or words. the author of Passage B similarly considers the importance of words and music and reaches a different conclusion, arguing that the elements of music and poetry/ words in opera are united and cannot be judged in isolation.
(E) How is opera different from all other musical art forms? Incorrect. Neither passage compares opera to ALL other musical art forms.
Let me know if this makes sense and if you have any other questions.
