Section C & D - Interviewable or not?

My new SW has been attempting to do section C with almost every  resident. She codes "yes" the interview should be conducted unless of course the resident is non verbal or 100% confused and unable to respond to even the most basic care need questions. . But sometimes we find during section C interview that the resident cannot respond to that level of conversation, so she codes " refused to answer or non sensical answer" and moves on to the staff interview. Then she codes section D as "no" interview should not be conducted. Is that acceptable - yes to section C but no to section D? She feels that if the resident cannot repeat three words , he certainly won't be able to respond to the more  involved questions in section D. Just looking for the opinions of others.