Question from GMAT prep -minority majority students

[yxlucy321]

Here is a question I have a problem with:

According to a survey of graduating medical students conducted by the Association of American Medical Colleges, minority graduates are nearly four times more likely than are other graduates in planning to practice in socioeconomically deprived areas.

a. minority graduates are nearly four times more likely than are other graduates in planning to practice
b. minority graduates are nearly four times more likely than other graduates who plan on practicing
c. minority graduates are nearly four times as likely as other graduates to plan on practicing
d. it is nearly four times more likely that minority graduates rather than other graduates will plan to practice
e. it is nearly four times as likely for minority graduates than other graduates to plan to practice

I picked a, the correct answer is c. Is it the problem with 'in planning to practice' or we cannot use 'four times more likely than'?

Thank you so much!

Kate

[yxlucy321]

Could anyone help me with this one?

Thanks!

Kate