Sentence Correction

1) Psycholinguists know that a child produces speech by imitating adults, but they do not know how he learns to distinguish significantly different phonemes or how he comes to ignore meaningless variations among speech sounds.

A) by imitating adults, but they do not know how he learns to distinguish significantly different phonemes or
B) by imitating adults, but they do not know how either how he learns to distinguish significantly different phonemes nor
C) Through the imitation of adults,but they neither know he learns to distinguish significantly different phenemes nor.
D) Through the imitation of adults,but they do not know either how he learns to distinguish significantly different phenemes nor
E) by imitating adults, but they do not know how he learns to distinguish significantly different phonemes nor

OA : A

2) Brief psychotherapy requires far fewer hours and costs far less money than traditional psychoanalysis and so will hopefully prove to be an effective treatment for many of the large amount of people currently seeking therapy
A) will hopefully prove to be an effective treatment for many of the large amount
B) will prove hopefully to be an effective treatment for many of the large amount
c) hopefully prove to be an effective treatment for many of the large number
D) Will, it is hoped, prove to be an effective treatment for many of the large number
E) Will, it is hoped, prove to be an effective treatment for many of the large amount

OA : D

Kindly provide the explanation for the above questions?

Thanks in Advance.
DJ