A hydrocarbon compound burns with a non-luminous flame. Which hydrocarbon type does it indicate?

Question

$\begin{array}{1 1} \text{a.Alicyclic hydrocarbon } \\ \text{b. Aromatic hydrocarbon} \\ \text{c. Unsaturated hydrocarbon} \\ \text{d. Acyclic hydrocarbon.} \end{array}$