The Following Information Is Available for Some of Coca-Cola's Segments

The following information is available for some of Coca-Cola's segments (all amounts are in millions):
$\begin{array}{|l|r|r|r|}\hline& \begin{array}{c}\text { North } \\\text { America }\end{array} & \text { Africa } & \begin{array}{c}\text { Latin } \\\text { America }\end{array} \\\hline \text { Segment sales } & \$ 6,264 & \$ 694 & \$ 2,089 \\\hline \text { Segment operating income } & 1,494 & 224 & 1,033 \\\hline \text { Segment average assets } & 4,869 & 541 & 1,443\\\hline \end{array}$
a. Determine the segment return on assets for each geographic segment
b. Comment on the results. How do the segments compare with respect to profitability?