Read the following context and choose the best option to answer the question.
Context: I am pretty sure I just made my brother the happiest guy on the face of the planet . He has been a Mustang car nut for as long as I can remember . Him and his friends are always going out buying new parts , helping each other put them on , and all that good fun stuff . It 's something I never understood , but oh well he loves to do it .
Question: What may be the cause for their brother 's happiness ?
Options: 
A. None of the above choices .
B. They bought their brother parts for his Mustang .
C. They had bought their brother a Mustang car .
D. They took their brother to a car show .


B