This is another "British English vs American English" question. In British English the verb forms are: get, got, got. In the US they are: get, got, gotten. So it depends if your examiners want Brit eng or Am Eng or they are imparcial - I, for one, admit both as correct. Hope this helps

Both are correct, but it's better to ask an American speaker the differences between "have got" and "have gotten". Or, you can do some research to find the difference. Apparently, it's not a simple case of "UK-got" = "US-gotten". That's a can of worms right there! :)

If you are learning British English, there's no problem, because we don't use the word 'gotten' at all. In British English, 'got' is both the past simple form and the past participle form of the verb 'to get' . As you know, it has many meanings. Here are some examples in the past simple: eg I got tired = I became tired I got a present for my birthday = I received I got to school late = I arrived In British English, the past participle is also 'got'. He has (or He's ) already got off the bus = He has already left bus In British English, especially in informal and spoken language, we also use the expression 'have got' as an alternative form of 'have' when you are talking about possessions and or what 'belongs' to you. Have you got any brothers? = Do you have any brothers? I haven't got much money = I don't have much money In these examples, the word 'got' has no actual meaning. It's just part of the expression 'have got'. 'Have got' means the same as 'have'. It's just there to make things easier to say and understand. 'I've a cold' is quite hard to hear, because the 'have' disappears, whereas 'I've got a cold' is much clearer. In American English, the past participle is 'gotten'. This word doesn't exist any more in British English, apart from in the verb 'to forget' (forget-forgot-forgotten). As Peachey suggested, you should wait for an American English speaker to explain how 'gotten' is used on the other side of the Atlantic.