Question

which format would be used to give personal opinions, often using links to other sources and websites? a a personal blog b a friendly letter c an advertising website d a online reference book

Explanation:

个人博客是用于分享个人观点的网络载体，通常可以插入其他来源或网站的链接；友好信件以私人交流为主，一般不会大量使用外部链接；广告网站以推广产品或服务为目的，并非侧重个人观点分享；在线参考书以提供权威参考内容为主，不以个人观点表达为核心。

Answer:

A. A personal blog