A vs. of vs. none

1. Which of the sentences above is correct?-- B and C

2. If two or more are correct, what is the difference between them? -- No difference in meaning. Also, I wonder how "of" changes the meaning of the sentence.-- It doesn't.

Thank you. I see the word "help" is a countable noun that's why an article is used. If it's countable, then the plural form is "helps". But I don't usually hear this form. Is it correct to say: "Your helps are truly appreciated,"?

I see the word "help" is a countable noun that's why an article is used. If it's countable, then the plural form is "helps".-- Not necessarily. It becomes reclassifed only in the instance where the modifier permits it here.
But I don't usually hear this form.-- I think you never do.
Is it correct to say: "Your helps are truly appreciated,"? -- No.

Thank you for your response.

Mister MicawberNot necessarily.

If I understood correctly this expression, it means there is a possibility?
That is, the noun form "helps" would be correct. Please confirm.

Mister MicawberIt becomes reclassifed only in the instance where the modifier permits it here.

I'm sorry

I mean that because a noun is made countable in one instance by reclassification, it does not necessarily take a plural form, and 'help' does not.

Thank you for that clarification. It makes sense to me now.