Official Explanation
Read the Original Sentence Carefully, Looking for Errors
The non-underlined portion of the sentence contains the first half of the correlative conjunction "not only ...." This conjunction must be completed by but also, and the second part must be in parallel form with the first part. Here, only also shows up in the underlined portion. Moreover, the first part is "not only hailed," while the second part is "[but] also been credited." To be parallel, the helping verb "been" must precede the conjunction in the second part, just as it does in the non-underlined first part. Finally, the introduction of the subject "it" in the underlined segment disrupts the parallel structure of the correlative conjunction, which should connect the verb "hailed" to another verb.
Note, too, the phrase "credited for." It is correct to say, The telephone is given credit for revolutionizing communication, but you must say, The telephone is credited with revolutionizing communication. Eliminate (A) and seek a choice that uses the not only ... but also construction and the credited with idiom correctly.
Scan and Group the Answer Choices
Like (A), (D) begins with "it" and omits the necessary "but," and (C) also inserts an "it" into the not only ... but also construction. (B) and (E) both begin with "but also credited."
Eliminate Choices Until Only One Remains
Along with (A), eliminate (C) and (D) for violating parallelism. Also eliminate (E), which fixes this issue but continues to use the idiomatically incorrect phrase "credited for." Only (B), the correct answer, includes both "but" and "also," uses parallel structure with "not only hailed... but also credited," and pairs "credited" with the proper preposition "with."
TAKEAWAY: When an underlined segment contains part of a correlative conjunction, make sure that the conjunction is complete and that the words or phrases it connects are parallel.