Self supporting arches for furnace roofs can be fabricated using silica bricks but not using magnesia bricks. Why?

A. Silica has a significantly lower thermal expansion coefficient than magnesia at high temperatures

B. Silica has a significantly higher thermal conductivity than magnesia at high temperatures

C. Silica has a significantly lower melting point than magnesia

D. Silica is significantly more acidic than magnesia

Answer: Option A