If the reporter would have known the landlord's side of the story, she would not have written an article so favorable to the 81-year-old tenant.
(A)
would have known the landlord's side of the story, she
would not have written
using "would have" in the IF clause is
INCORRECT___________________________________________________________
(B)
would of known the landlord's side of the story, she
would not of written
using "would" in both IF and THEN clauses is
INCORRECT___________________________________________________________
(C)
had known the landlord's side of the story, she
would not have writtenpast perfect in IF clause should be followed by "would have/would not have" + verb in THEN clause.
___________________________________________________________
(D) had known the landlord's side of the story, she would not have
wrote___________________________________________________________
(E)
knew the landlord's side of the story, she
would not have written
simple past tense "knew" in IF clause should be followed either by simple past or "would" but not "would have"
INCORRECT___________________________________________________________
Hence option C