Is there a post office near your school?yes,there is (one it this that) near here.

题目

Is there a post office near your school?yes,there is (one it this that) near here.

答案

one一般用来代替前文提到,在后文又出现的名词单数形式
it表泛指
this和that都是特指,"这"或"那".
所以这题选one