Answer: Option C
Discreet : careful and prudent in one's speech or actions, especially in order to keep something confidential or to avoid embarrassment.
Undifferentiated : not different or differentiated.
Uncritical : not expressing criticism or using one's critical faculties.
Insensitive : showing or feeling no concern for others' feelings.
Indiscriminate : done at random or without careful judgement.
Synonym of Indiscriminate is Uncritical