试图引用“this”引用当前字符串对象。不确定我是否正确行事

Scenario
quiz problem, final exam tomorrow and this problem makes NO sense to me, someone please please please show me the code segment that would fit the criteria. everything I try has failed. my biggest problem is I have no idea how to reference "this". So I have no idea if I am doing it right or not my teacher will not give me a yes or no answer, I am going to post my attempt at the code below and hopefully someone will correct my mistakes. I would be forever in your debt! quiz problem, final exam tomorrow and