Which reaction shows the formation of a compound combining silicon dioxide and calcium oxide?

The reaction between silicon dioxide and calcium oxide results in the formation of calcium silicate, represented by the chemical formula CaSiO₃. This is an example of a synthesis reaction where two oxides react to form a compound. Silicon dioxide (SiO₂) provides the silicon, while calcium oxide (CaO) provides the calcium, combining them to produce the crystalline structure of calcium silicate.

In this context, the other options illustrate different types of reactions that do not involve silicon dioxide and calcium oxide, nor do they produce calcium silicate. For instance, carbon reacting with carbon dioxide produces carbon monoxide, decomposition of calcium carbonate results in calcium oxide and carbon dioxide, and carbon combining with oxygen forms carbon dioxide. None of these reactions form the compound in question, which emphasizes the specificity of the reaction of interest.