A subordinating conjunction is a conjunction that introduces a subordinate clause. For example although, because, etc. So the correct answer is because.
Hope this helps! :)
Electricity today is a very important source of life. Almost all life activities depend on electricity. Power cuts or power outages cause some activities to stop. Power outages are caused by other electrical activities, of course, which have the same path. For example, the installation of several towers or power poles, time-consuming cable repairs. In addition, there are causes outside of electrical activity, namely the occurrence of fire disasters. To avoid things that are not desirable, of course, must be quick to respond to this by turning off electricity en masse. What can happen, of course, is that neither party benefits.

There are two stories of how Pecos Bill died. One claims that he lay down on the sidewalk, and laughed until he died. Another one says that he died after eating a meal of barbed wire washed down with nitroglycerin. Nobody can claim which is real tho