The symbol for calcium is Ca, the symbol for sulfur is S, and the symbol for calcium sulfide CaS. Which of the following best describes this chemical reaction: $Ca (s) + S (s) \longrightarrow CaS (s)$?

Question

$\begin{array}{1 1} \text{(a) Cobalt combined with sulfur forms calcium sulfide} \\ \text{(b) Calcium combined with sulfur forms calcium sulfide.} \\ \text{(c) Carbon combined with sulfur forms calcium sulfide.} \\ \text{(d) Cadmium combined with sulfur forms calcium sulfide.} \end{array}$