Which of the Following Will Cause a Deadlock

Multiple Choice

Which of the following will cause a deadlock?

A) Transaction T1 requests an exclusive lock on data A at the same time as transaction T2
B) Simultaneously, transaction T2 places an exclusive lock on data B, then requests one on data A
C) Transaction T1 places an exclusive lock on data A, then transaction T2 requests a shared lock on data A
D) Transaction T1 places an exclusive lock on data A, then requests one on data
E) Transaction T1 and T2 modify data A without any lock