Usage of normal, average, regular or ordinary

[Sophie]

In my exercise book, there is a question like that:
Free medical treatment in this country covers sickness of mind as well as ........ sickness.
A. normal
B. average
C. regular
D. ordinary
I don't know which to choose. Can anyone help me?
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On earth there is nothing great but man, in man there is nothing great but mind.

[Mister Micawber]

.
Ordinary-- but it is not a very good question. Mental illness is as 'ordinary' as physical illness. The other words do not work, as you will find if you check your dictionary.
.
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Native English teacher at Mister Micawber's

[Giang93]

http://www.bbc.co.uk/worldservice/learningenglish/grammar/ask_about_english/080107/
You can see a sufficient explaination in this link

[Duc]

[Mister Micawber]

.
Illness is not a normal condition; health is.
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Native English teacher at Mister Micawber's

[Giang93]

In my opinion , the answer here is D . ordinary . Because " normal " is used to say about something that is alway in our life . you can consider it as a familiar thing , not particularly good or impressive .

[Sophie]

I agree with you, Giang.
Thank you very much, my friends!
_________________
On earth there is nothing great but man, in man there is nothing great but mind.