Elsevier cas-sc document class: cannot print bibliography

Question

\documentclass[a4paper,fleqn]{cas-sc}

\begin{document}
\begin{thebibliography}{1}
\bibitem{DLC_DR}
Stenner, Karen, Elisha R. Frederiks, Elizabeth V. Hobman, and Stephanie Cook. "Willingness to participate in direct load control: The role of consumer distrust." Applied energy 189 (2017): 76-88.
\bibitem{Price_DR}
Takano, Hirotaka, Asuka Kudo, Hisao Taoka, and Atsumi Ohara. "A basic study on incentive pricing for demand response programs based on social welfare maximization." Journal of International Council on Electrical Engineering 8, no. 1 (2018): 136-144.
\end{thebibliography}
\end{document} 

Answer 1

You need to load a citation management package with suitable options, e.g.,

\usepackage[numbers]{natbib}

A full MWE:

Note that I would use smart rather than dumb (") quotes around the titles. I would also use en-dashes rather than simple dashes to indicate numeric ranges (see the page ranges below).

\documentclass[a4paper,fleqn]{cas-sc}
\usepackage[numbers]{natbib} % <-- new
\begin{document}

\noindent
\cite{DLC_DR,Price_DR}

\begin{thebibliography}{1}

\bibitem{DLC_DR}
Stenner, Karen, Elisha R. Frederiks, Elizabeth V. Hobman, and 
Stephanie Cook. ``Willingness to participate in direct load control: 
The role of consumer distrust.'' Applied Energy 189 (2017): 76--88.

\bibitem{Price_DR}
Takano, Hirotaka, Asuka Kudo, Hisao Taoka, and Atsumi Ohara. ``A basic 
study on incentive pricing for demand response programs based on social 
welfare maximization.'' Journal of International Council on Electrical 
Engineering 8, no.~1 (2018): 136--144.

\end{thebibliography}
\end{document}