3a is good. By inquiring the quality information of the whole brick, we know that the whole brick has three grades, namely aaa excellent grade, aa first grade and A grade. And aaa is the best grade, better than others. Whole brick refers to the low water absorption brick with the same color between the blank and the brick surface. The main purpose of whole brick is to make the exposed brick blank keep the same color with the brick surface after secondary processing such as chamfering and grooving, so as to maintain the sense of unity in design.