Directions: A part of the sentence that has been underlined has an error. Select the option that is the most coherent and precise representation of the underlined part.

Of the many decisions facing the energy commission as it meets to decide on new directions for the 21^st century, the question of the future of nuclear energy is for certain more perplexing.

'For certain' is an awkward and less precise phrase than 'certainly'. Since we're comparing the nuclear energy question against multiple other decisions, we need the superlative form 'the most perplexing', not the comparative 'more perplexing'. Option D uses 'certainly' (the standard adverb) with 'the most perplexing' (the correct superlative). Options A, B, and C use either wrong comparative forms or awkward phrases like 'for sure'.