Which of the following is not a form of energy?
a. electrical
c. thermal
b. nuclear
d. magnetic

An electrical energy is the movement of charge from one point to another. Thermal energy is the movement of heat from one point to another. Nuclear energy is the movement of solar from the sun. Magnetic is a force that attracts a body to another. Magnetic is not a form of energy.

Electric energy is the energy caused by the movement of the electric charges. The moving electric charges form the kinetic energy, thus electrical is the from of energy.

Thermal energy is the energy which usually comes from the heat.This heat is generated by the movement of tiny particles within an object. Thus, thermal energy is the form of energy.

Nuclear energy is the energy which comes from the splitting atoms in a reactor to heat water into steam and generate electricity. Thus, nuclear energy is the form of energy.

The magnets cannot be used to generate energy, as it is kind of a force which attracts a body from the another body, therefore the magnetic is not the form of energy.

Thus, option D is correct.

There could be a number of factors that affect the movement of surface water in sources such as, streams and rivers. These may include wind, bed slope, type of rocks, obstructions (say by vegetation), bed shape, etc.

The wind creates currents and causes motion. Bed slope or steepness of bed may also define how fast or slow the surface water will move. A steeper slope is associated with higher velocities, while a gentle slope will cause slow flow. Higher velocities will also enable movement of materials carried by river (such as silt), while slower velocities would force the settlement of such material, causing obstructions in its own path. Any obstruction in the path of water causes change of course (depending on the size or magnitude of obstructions). This can be seen in embankments and cutting by the streams. The rock types in the region and bed also affect the water motion. Another important factor related to the flow is the interaction between surface and groundwater. 

link: https://www.enotes.com/homework-help/what-three-factors-describe-movement-surface-water-507498

Hope this helps.