Option A is correct because -y transforms the noun into an adjective, meaning 'characterized by'. For example, in the phrase "one stormy night", the adjective 'stormy' modifies the noun 'night'. Option B is correct as the suffix '-ful' forms the adjective 'stormful' and attributes the meaning 'full of', in "they had a stormful voyage", the adjective 'stormful' modifies the noun 'voyage'. The words 'stormious' and 'stormish' do not exist in the English language, hence options C and D are incorrect.