Fill in the missing event that causes deadlock in a database. there are two processes (p1 and p2), each of which needs to update two records (r1 and r2) and the following sequence leads to a deadlock:
1. p1 accesses r1 and locks it.
2. p2 accesses r2 and locks it.
3.
4. p2 requests r1, which is locked by p1.
a. p2 releases r1.
b. p1 requests r2, which is locked by p2.
c. p2 releases r2.
d. p1 requests r1 again.

1. which of the following statements are true about routers and routing on the internet. choose two answers. a. protocols ensure that a single path between two computers is established before sending packets over it. b. routers are hierarchical and the "root" router is responsible for communicating to sub-routers the best paths for them to route internet traffic. c. a packet traveling between two computers on the internet may be rerouted many times along the way or even lost or "dropped". d. routers act independently and route packets as they see fit.