If we observe the components:

B and A form a logical pair: "Ravana came in the form" (B) followed by "of an old and infirm sanyasi" (A)

This creates a complete and grammatically sound clause: "Ravana came in the form of an old and infirm sanyasi."

C, E, and D form a block that describes the sequence of Ravana’s action:

C: "and lifting Sita along with"
E: "the piece of ground on which she stood"
D: "put her on his chariot"

Together, these form a continuous and meaningful sequence: "Ravana came in the form of an old and infirm sanyasi and lifting Sita along with the piece of ground on which she stood, put her on his chariot."

The conjunction “and” at the beginning of C indicates it should follow an independent clause which is formed by the B-A pair.