(A) Incorrect . For the reasons mentioned above.
(B) Incorrect . For the following reasons:
- As is, "it will no longer" seems like an independent clause. To indicate that it is also a part of "hope", "that" needs to be repeated before this clause. In general, "that" needs to be repeated for every clause for parallelism and also for meaning clarity.
- Since the beginning modifier is "by increasing_", it is highly preferable to have the subject of the clause the entity that will be doing the action of "increasing". However, in this case, "enough" is the subject of the clause, leaving one in doubt "who has increased_?"
- The position of "no longer" after "will have" is incorrect. The correct positions are "will no longer have to" and "no longer will have to".
(C) Incorrect . "having" is not parallel to anything before ?and?.
(D) Incorrect . For the following reasons:
- "having" acts as a verb-ing modifier modifying the preceding clause and thus needs to make sense with the subject of the preceding clause, which is "enough". Clearly, "having" doesn?t make sense with "enough".
- Problem no. 2 of option B.
(E) Correct . Both the problems of the original sentence have been rectified in this option.