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 .
According to the above context, choose the best option to answer the following question.
Question: Why may the narrator 's legs be so sore and tired ?
Options:
A. They took a train .
B. They took a car .
C. They took a boat .
D. They walked instead of taking the bus .


D