I forgot to top - up my card ! " And with no small change with us , we were forced to walk from the apartment beside Greenview Sec all the way to Pasir Ris MRT station . I could have taken the bus , but being a good person that i am , i walked with my sister .

Question: Why may the narrator 's legs be so sore and tired ?
Answer: They took a train .They took a car .They took a boat .They walked instead of taking the bus .