In the meandering of river, water flow at outer edge is at higher elevation that inner age water force applied by water at outer edge is higher that inner edge.Because of this force (pressure) difference a secondary flow is generated and river erode outer bank and deposit the material at inner side of the bank.
The correct answer is option A, Most rivers curve or meander
Reason:
The water at the outer edge of the river are at high elevation as compared to inner edge and thus the pressure at outer edge is high as compared to the inner edge. Due to this pressure difference the secondary flow is generated which causes the slope material transportation from outside to the inner side of the river.
To show that magnets repel, you must place the strong and weak magnets to another magnet with their poles being both south or both north facing eachother.
To show they attract, place opposite poles near eachother.