Nitpicking "if" structure

So what would be better?

def method
  if !event
    return nil
  end
  return Table.find_first_by_name("oak")
end

def method
  return nil unless event
  return Table.find_first_by_name("oak")
end

def method
  return !event ? nil : Table.find_first_by_name("oak")
end

I figured the first is a bit clearer, but longer...and while the third is shorter, I'm not sure that a coverage tool would flag parts of it as uncovered. And the second...well, having two returns seem kinda ugly. What do you think?