The R and S Proteins From $\lambda$ Phage Can Form Complexes Called Holin and Spanin

The R and S proteins from $\lambda$ phage can form complexes called holin and spanin.Which of the following describes the process that these complexes participate in?

A) Assembly of the virion.
B) Replication of the viral genome.
C) Packaging of the viral genome into the head
D) Excision of the viral genome from the host chromosome.
E) Lysis of the host cell to release virions.