An open end wrench.
Flare nut wrenches are just small wrenches, usually 5/16 or similar with a slot to pass over the pipe.
A wrench is callsified as a tool.
A flare wrench is the proper tool. Looks like a box end wrench with just a slot cut through the end to go over the line. Grips on 3 sides of the nut so that hopefully it doesn't round off the sides of the nut. Some WD-40 or similar wouldn't hurt and a hammer to give the wrench a sharp tap to break contact on the nut. Vice grips if you have to.
A wrench is a tool used to turn a bolt or nut.
a wrench
The bottom fitting is a quick connect fitting. You usually use a special tool to release this fitting. Some auto parts stores will lend you the necessary tool for free. The top line will be a flare fitting, which will require the proper sized end wrench or line wrench to remove.
Most good auto parts or tool stores will stock that.
a ratchet
A combination wrench is a tool that has two ends used to loosen or tighten a nut or bolt. One end typically has the appearance of a U or open jaw, the other end is a close circle with grooves that operates similar to a socket wrench.
Depends if your looking for a Double Flare or single flare and that would depend on the working pressures involved.In any event need a flaring tool of the proper size
some examples of turning tool are Monkey Wrench, Adjustable Wrench,Allen Wrench
some examples of turning tool are Monkey Wrench, Adjustable Wrench,Allen Wrench