【正确答案】 C

【答案解析】[解析] 根据文章末尾We found out that patients who had been dealt with openly and frankly were better able to cope with the approach of death and finally to reach a true stage of acceptance prior to death．作者在这里说的had been dealt with openly and frankly指的是上文的to be kept up-to-date on their medical condition and to be told when the end was near，可以断定作者认为“垂死的病人知道他们的真实情况”，选项C正确。