Sentence Correction

Source: Kaplan GMAT Premier
Questions: Brief psychotherapy requires far fewer hours and costs far less money that 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 will 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

Options a,b and e are out due to "amount". I am perplexed between c and d. I am not sure if I can use it is hoped.....Please help

Already discussed @ https://www.beatthegmat.com/brief-psycho ... 55474.html

I have prepared my notes from reliable resources.

Acc to them

'hopefully' is never correct in GMAT

'It is hoped ' is preferred instead.

thanks a lot guys....