Highly Pure Silicon for the Manufacture of Solid State Electronic

Highly pure silicon for the manufacture of solid state electronic devices is made on an industrial scale by

A) reduction of SiCl₄(g) with hydrogen gas.
B) reduction of SiO₂(s) with coke (amorphous carbon) .
C) thermal decomposition of SiH₄(g) .
D) reduction of SiCl₄(g) with an alkali metal.
E) reduction of SiO₂(s) with aluminum.