Answer:
silicon-oxygen tetrahedron is the correct answer.
Step-by-step explanation:
The main building block of a silicate mineral is silicon-oxygen tetrahedron. Silicon-oxygen tetrahedron belongs to the anionic group and the silicon atom is surrounded by four oxygen atom, arranged to determine the edges of a tetrahedron.
This silicate ion consists of one silicon atom, placed in the middle of a tetrahedron and surrounded by four oxygen atom, placed at vertices of a tetrahedron.