Just to confuse you even more, these all are "flexible" type cables:
Armored clad types AC (e.g., BX) and MC;
Romex family NM, NMS, NMC;
Flexible metal family FMC, FMT, liquidtight FMC and liquidtight FNC.
All of the above come with insulated copper conductors. This wire is called THHN, which is the designation for the plastic jacket that covers the copper. All the nonmetallics have a grounding (green) conductor as well as the hot (black) and neutral (white). What you use depends on the application but AC is the most common, with or without the green. I would suggest the MC type, which has a green ground. Isolate the ground, meaning attach the green wire to the green screw of the outlet, which itself has a spacer to isolate it from the metal outlets mounting box.
Armored clad types AC (e.g., BX) and MC;
Romex family NM, NMS, NMC;
Flexible metal family FMC, FMT, liquidtight FMC and liquidtight FNC.
All of the above come with insulated copper conductors. This wire is called THHN, which is the designation for the plastic jacket that covers the copper. All the nonmetallics have a grounding (green) conductor as well as the hot (black) and neutral (white). What you use depends on the application but AC is the most common, with or without the green. I would suggest the MC type, which has a green ground. Isolate the ground, meaning attach the green wire to the green screw of the outlet, which itself has a spacer to isolate it from the metal outlets mounting box.