1.When HM Treasury produced long run forecasts of the impact on the UK economy of Brexit they used a number of major assumptions, notably:

(a.)Gravity models and other procedures could be used to indicate the extent of reduction in UK-EU trade.

(b.)There would be a strong relationship between the extent of UK-EU trade and UK productivity.

(c.)It was meaningful to project forward a baseline for what UK economic growth would have been in the absence of Brexit.

Take ONE of these assumptions and evaluate it very briefly. include any sources used