#1 is incorrect because concise language involves using to-the-point, non-fluff language and vocabulary to get one's ideas across--this is obviously necessary for effective writing.
#2 is incorrect because concrete nouns are simply physical nouns that aren't abstract, such as "I", "You", "Michael", "Table", "Cat". Concrete nouns are obviously used effectively in writing constantly.
#3 is incorrect because these expressions are formal rather than informal and will therefore fit well into most academic writing.
#5 None of the above is therefore correct.