A. how anxious I have been B. so anxious I have been

C. how I have been anxious D. I have been so anxious

【答案】A

【解析】

试题分析：考查宾语从句。句意：你不知道这为她的安全有多么的焦虑。 Have no idea后面引导宾语从句，how adj +主语+谓语，故选A项。