Two techniques that can be applied in writing or orally for indirectly criticizing someone or something are
sarcasm
verbal irony
connotation
tone

Explanation:

Sarcasm is the utilization of comments that obviously mean the opposite they state, made so as to offend someone or to scrutinize something hilariously.  

Verbal irony happens when individuals state one thing yet mean another.  It enables perusers to practice a tad of recognition and omniscience.

answer; /// i do believe the correct answer is (c) public education;