To speak habitually of the "truly needed" is gradually instilling the notion that many of those who are just called "needy" actually have adequate resources; such a conclusion is unwarranted.

a) Original sentence
b) To speak habitually of the "truly needed" is instilling the notion gradually
c) To speak habitually of the "truly needed" is gradually to instill the notion
d) Speaking habitually of the "truly needed" is to instill the gradual notion
e) Speaking habitually of the "truly needed" is instilling the gradual notion


In my opinion the answer should be d),but the correct answer is c)

Does anyone has any explanations??