The cellular complexes GroES and GroEL are involved in the assembly of the λ phage virion.Which of the following describes their function during assembly?

A) They package the viral genome into the head.
B) They act as chaperones in the formation of the portal vertex.
C) They act as a scaffold for the assembly of the tail.
D) They acts as a scaffold for the assembly of the head.
E) The cleave concatemers of the viral genome during assembly.