For the Year Ended October 31,2009,NB Financial Group (National Bank)reported

For the year ended October 31,2009,NB Financial Group (National Bank)reported income before tax of $2,160 million and income tax expense of $274 million,for an effective tax rate of 12.7% ($274m / $2,160m).In the notes to the financial statements,NB's disclosures included the following information:
$$\begin{array} { | l | r | r | } \hline \textbf { Reconciliation of statutory and effective rates } & \begin{array} { l } \textbf { Amount } \\( \textbf {\$ millions) }\end{array} & { \begin{array} { c } \textbf { Rate } \\\textbf{(\%)}\end{array} } \\\hline \text { Combined Canadian federal and provincial income } & & \\\text { tax rates at the statutory rate } & 734 & 34 \\\hline \text { Increase (decrease) resulting from: } & & \\\hline \text { Tax exempt income } & ( 180 ) & ( 8.3 ) \\\hline \text { Foreign operations subject to different tax rates } & ( 210 )& ( 9.7 ) \\\hline \text { Change in tax rate for deferred income taxes } & 14 & 0.6 \\\hline \text { Intangible assets not deductible for tax purposes } & 8 & 0.4 \\\hline \text { Recovery of prior year's income taxes } & ( 80 ) & ( 3.7 ) \\\hline \text { Other } & ( 12 ) & ( 0.6 ) \\\hline \text { Income tax expense and efective tax rate } & 274 & 12.7 \\\hline \text { Dollars amounts in millions) } & 2009 & 2008 \\\hline \text { Deferred income tax assets } & \$ 1,080 & 1,205 \\\hline \text { Deferred income tax liabilities } & 750 & 700 \\\hline\end{array}$$ Requirements:
a.From NB's disclosures provided above,identify any permanent differences.
b.In which direction did the tax rate change from 2008 to 2009?
c.Refer to the line "Recovery of prior years' income taxes" in the above disclosures.What does this information imply about NB's treatment of tax losses in prior years?