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 !

Question: Why could she have walked ?
Answer: None of the above choices .She could n't drive a car home .The bus was slow .She did n't spend $ 30 on a cab .