Match the following MPI routines with their intended purposes.

D$.$

MPI$\_$Init

A$.$

MPI$\_$Comm$\_$size

C$.$

MPI$\_$Comm$\_$rank

B$.$

MPI$\_$Finalize

F$.$

MPI$\_$Send

E$.$

MPI$\_$Recv

A$.$

Return the total number of processes in a communicator specified in the routine's argument

B$.$

Signal the destruction of MPI processes and return to a sequential execution state.

C$.$

Return the rank of a process with respect to a communicator specified in the routine's argument

D$.$

Initialize the support of MPI for the number of processes specified by the $-$np flag of the mpirun command

E$.$

Receive a message from a process as specified in the routine's arguments

F$.$

Send a message to a process as specified in the routine's arguments