单选题 What does the word "Which" in line 3 of the third paragraph refer to?

【正确答案】 D
【答案解析】[考核题型] 细节题
[解析] which引导一非限定性定语从句，先行词为kevlar，即which指代Kevlar，famous for... vests 也做定语，故D是答案。