In the book "Adventures of an IT Leader," why doesn't the IT team know for sure whether or not an intrusion by hackers into IVK's systems has

occurred?

a$.$ The IT team does know for sure $-$ hackers are inside the system because a database file was renamed

b$.$ Some departments aren't following proper database development protocols, so IVK can't tell what belongs in the production system

and what does not

c$.$ John Cho forgot to make backups of the development environment

d$.$ Barton failed to convince the Board of Directors to invest in the major infrastructure replacement project