the question states the structure of ethanol and it also states the formula must be illustrated. i recommend drawing the structural formula of reactants and products, and yes, add the states in (very important). and also, because it is out of 4 marks, there is a key that more vital information is required, so construct a short statement or paragraph explaining how ethanol undergoes complete combustion and because of the oxygen atom within the ethanol molecule does not allow the production of CO (carbon monoxide) and C (carbon).
and also the key verbs hint on what is required of you to answer the question.
that'll be more then enough to answer the question and get full marks