It seems you are using a old copy of the Revision Kit because Blipton is not included in the current edition.
However I do have the original exam question 🙂
The US inflation rate is only relevant for calculating the nominal cost of capital for Blipton. Given that Blipton is in Dubai and reports and accounts in dollars, it is reasonable to assume that the relevant inflation rate is the dollar inflation rate – i.e. the US inflation rate.