Why not future continuous?

[Hucky]

Hiya,
In a practical grammar book, chapter on future forms, I came across the following example sentence:
It´s a very good question, very direct, and (not answer) it.
The student has to decide on one or more future forms to go with the context. Looking up the answer in the key it says that the going to-future and the will-future match here, thus rendering the sentences into:
a) It´s a very good question... , and I´m not going to answer it.
b) It´s a very good question..., and I won´t answer it.
I wonder why the will continuous/progressive doesn´t work here.
E.g.: It´s a very good question..., and I won´t be answering it.
I´d say that version sounds more polite, doesn´t it.
In case the latter version is acceptable, if not even preferable to b), how could you account for the differences between them?
Best thanks and greetings
Hucky

[The Dude]

There is indeed a subtle difference between the first two.
In a), the reply would be followed by a reason for not answering, eg: 'I'm going to ask John to answer it because I'm sure he knows'. Typical situation - pupil asks question of teacher, who redirects it to another student in order to wake him up!
In b), there is a blunt refusal to answer. It's an odd response, really. More natural would be to say 'I can't answer', meaning that I just don't know.

As for 'I won't be answering it', it's no more polite than anything else. In fact it's rather less polite than a). I'd say it has to be qualified with a time clause, such as 'I won't be answering it today as there's no time left. Ask me again tomorrow.'

[gordib]

The use of future forms in English is extremely complicated. The writers of text books try to keep it as simple as possible.
In many cases the use of 'will' is almost equivalent to the German 'wollen' (want to).
"I will not answer the question" = roughly "It is not my desire/wish to answer the question". (So much for 'will' being described as the "pure" future!).
"I am not going to answer the question" expresses to the listener that something just won't happen. The speaker does not infer whether it is his wish or if, for example, there are time constraints, etc.
Look at it this way:
"I will not answer the question" - [OK, understood. You do not want to.]
"I am not going to answer the question" - [Why not?]

The use of continuous forms is often a method of expressing politeness in English - even if the verb has, according to the rules, no continuous form!
Think = believe (NOT in the continuous). Yet look at this:
"I am thinking you have made a big mistake".
"I was thinking you have made a mistake."

So, right, guys. In this case the use of the future continuous is a more polite way to say ... "I do not want to".
"I will not be answering this question" [and if you dare ask me 'why not?', I will just answer 'Because!']

[The Dude]

Gordib, please check 'infer'! (New to this site, I'm hoping this is a Private Message - if not, sorry.)

[Hucky]

Dear Gordib and dear Dude,

Although in a nutshell I´d like to thank you both for your illuminating replies. Let me assure you that you have been of very great help to me. All the best to you!

May I perhaps come back to you with an additional question to you tomorrow evening?

[Vidor]

Progressive tenses are pointless. Shakespeare got along fine by using the simple present to express the present. We don't need a progressive tense to express something even MORE now than now.