I want to show you is my gratitude and respect for your continuous and selfless help.A. Th

问题补充：

I want to show you is my gratitude and respect for your continuous and selfless help.

A. That

B. Which

C. Whether

D. What

答案：

A. That

B. Which

C. Whether

(答案→)D. What

解析：句意：我想对你说的是，对于你连续的和无私的帮助，我表示感激和尊敬。通过分析句子结构，可知这个句子中包含一个主语从句，且引导词在从句中作宾语，表示“什么”的意思，故用What，选D。