Is there a significant difference in meaning between "欢迎你到中国来" and "欢迎你来到中国"?
I am a native speaker but not language specialist, thanks for @Earth Engine awared that.

In my opinion (not from authoritative textbook), strictly speaking, B. "欢迎你到..." means you are not in the place... we welcome you to there; "欢迎你来到" means you are already there, we welcome you.  

However, except very formal situation or someone who is extremely sensitive with language, most people in China will not care about the difference. In fact, I thought these two expressions are essentially the same in the beginning. It took me one minute to figure out there is a sutble difference.