Unlike the lungs and the kidneys, the liver is an organ well suited [o

Pre-thinking: We need to reinforce the statement that "Liver will be regenerated in the healthy adult within a few months"

(A) The success rate of liver transplants is slightly lower in children than in adults.
This option is comparing success rates in Children and Adults. so out of scope

(B) In removing the portion of liver for transplant there is danger of causing damage to the spleen of the donor, and that could necessitate the removal of the spleen.
Spleen removal is none of our concern but in any case, this statement some what weakens the conclusion. hence incorrect

(C) There is less danger that a transplanted organ will be rejected when the organ donor is a close relative of the recipient.
Doesnt add any additional weight to the statement "Liver will be regenerated in the healthy adult within a few months"

(D) There are so few suitable donors that about one-half of the babies with liver disease born in the United States each year die before they can receive a liver transplant.
Doesnt add any additional weight to the statement "Liver will be regenerated in the healthy adult within a few months"

(E) Each lobe of the liver functions separately, and it is possible to extract a portion of one lobe without disrupting critical liver functions.
This statement clearly complements the statement that "Liver will be regenerated in the healthy adult within a few months". So we have additional support and hence this strengthens our argument

IMO E is the correct answer as per the explanation above.