Who Stole Account Data from HSBC's Private Bank in Switzerland

Who stole account data from HSBC's Private Bank in Switzerland and how did HSBC learn about the data theft?

A) Account data was stolen by a former HSBC IT specialist;HSBC learned about the theft from French Authorities several years after the theft.
B) Account data was stolen by a group of hackers who cracked passwords;HSBC detected the data theft from their IT staff within a few days.
C) Malware was used to steal the account data;network intrusion detection systems detected the theft as it was happening.
D) Competitors stole the account data;HSBC learned about the theft months later when customers complained about identity theft.