Which sentence demonstrates the proper use of in-text citations according to MLA guidelines?

Darwin writes that "the shield may be as important for victory, as the sword of spear" (Darwin 107).
Darwin writes that "the shield may be as important for victory, as the sword or spear" (107).
Darwin writes that "the shield may be as important for victory, as the sword or spear" (Darwin).
Darwin writes that "the shield may be as important for victory, as the sword or spear" (The Origin of Species).

Question

Which sentence demonstrates the proper use of in-text citations according to MLA guidelines? 
 	
	Darwin writes that "the shield may be as important for victory, as the sword of spear" (Darwin 107).
	Darwin writes that "the shield may be as important for victory, as the sword or spear" (107).
	Darwin writes that "the shield may be as important for victory, as the sword or spear" (Darwin).
	Darwin writes that "the shield may be as important for victory, as the sword or spear" (The Origin of Species).

paki · Answer

it's A...