Marginal Modal Auxiliaries

What central modal auxiliary verb is 'ought to' a synonym of?
1. should
2. would
3. could
4. might
Which modal verb is commonly considered more formal and typical of written rather than spoken discourse?
1. ought to
2. should
Which of the two verbs listed below is commonly used with a full infinitive (ie infinitive with 'to')?
1. ought
2. should
When is it possible to use 'ought' without 'to'?
1. In elliptical constructions, eg short answers.
2. In any situation because 'to' is used with 'ought' only optionally.
3. When fronting the verb 'ought'.
4. Never.
What is the correct contracted negative form of 'ought'?
1. oughtn't
2. outn't
3. oughn't
4. ougthn't
Where may we freely use the negative contracted form of 'ought'?
1. British English only
2. American English only
3. British and American English both
4. nowhere