America was ( ) was first called "India" by Columbus.A)that

答案应填what,它在此引导表语从句,相当于 the place that,表示“……的地方”.句意为：美国就是最先被哥伦布称为“印度”的地方.如：
This is what they call Salt Lake City.这就是他们称为盐湖城的地方.
In 1492,Columbus reached what is now called America.1492年哥伦布到达了现在所称的美洲大陆.