4 0r 6 lb line?

new to bass fishing and getting ready to set up my rods for pond fishing [
21 acre golf course pond- shallow with not many hang up along edges other
than brush ].
Using Shimano stratic 2500 reels and 7 ft rods { long enought to clear
front of kayak when fish on ]
Now I need to decide what line to us--braided or mono- 4,5,or 6 lb.
And why that choice. Thanks
Joe the Elder
[fish are usually 0ne to two lb.]