an grammer quastion for SAT~~

<p>the question:
Having completed a course in art appreciation, Maureen and (I) (were) able to judge the paintings in the Museum of Modren Art (more criticial) than we had (before). (NO ERROR).</p>

<p>THE ANSWER IS C AND I DON'T KNOW WHY.
PLEASE HELP ME, THANKS.</p>

<p>It should be 'more critically'. An adverb, not an adjective, is necessary to modify the verb (judge).</p>