According to the Text, Which of the Following Is the Main

According to the text, which of the following is the main reason for British Airways employees going on a strike in 2003?

A) To protest against the introduction of swipe cards for electronic clocking-in
B) To protest against the strict security measures implemented due to concerns about terrorism
C) To declare their concerns about how the Severe Acute Respiratory Syndrome (SARS) epidemic might affect their safety
D) To strategically affect the governmental elections in Britain