Read the following context and choose the best option to answer the question.
Context: This morning started out innocently enough , except it took all of thirty seconds of me sitting at my desk before I felt something fall onto my head . I leaned forward and sort of shook my head and some gigantic ( well , moderately sized , but given the hour and the circumstance ... ) bug fell off my head and onto my keyboard . It did n't move . Was it alive ?
Question: Why did I feel something fall onto my head ?
Options: 
- Because something fell on my head .
 - Because I leaned forward .
 - Because I shook my head .
 - Because this morning started out innocently enough .


Because something fell on my head .