Match the rpm commands with their functions:
Command Functionality
1) rpm -U a) removes an existing package
2) rpm -F b) upgrades an existing package, and installs a new package if it is not already installed
3) rpm -i c) causes the package to be upgraded only if it is already installed but not to be installed
if it is not currently installed
4) rpm -e d) keeps the existing package and installs a new one
A.
1-b, 2-c, 3-d, 4-a
B.
1-b, 2-a, 3-c, 4-d
C.
1-c, 2-d, 3-a, 4-b
D.
1-c, 2-b, 3-d, 4-a