Identify two placeholder wait events that can be observed while a session is waiting to access a block. (Choose
two.)
A.
gc cr block busy
B.
gc current block request
C.
gc current block busy
D.
gc cr block request
E.
gc current grant busy
F.
gc cr grant busy
Explanation:
https://docs.oracle.com/cd/B19306_01/rac.102/b14197/monitor.htm#RACAD975
B,D