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This is the first time that Paul and I have n't coordinated spare keys for whoever 's car ends up at the airport when we 're both away . So I could n't drive his car home when I got home today . So rather than spend $ 30 on a cab , I spent $ 2 on the bus . It took me ALMOST AN HOUR to get home from the airport . I could have WALKED in that amount of time !

Why could she have walked ?
Pick your answer from: (I) None of the above choices . (II) She could n't drive a car home . (III) The bus was slow . (IV) She did n't spend $ 30 on a cab .
(III)