The answer is B) region of high pressure in a medium caused by a passing wave
Compression is the forcing of the molecules of a medium, be it water, air, or something else, as a wave passes by. This forcing together of the molecules raises the pressure of the medium in the area that the wave passes through.
The vector, the x-component and the y-component form a rectangle triangle where the vector is the hypothenuse and the x and y components are the two sides.
Calling

the angle between the vector and the horizontal direction (x), the two sides are related to

by

where vy and vx are the two components on the y- and x-axis. Using vx=10 and vy=3 we find

And so the angle is
1. neutral particles (neutrons) are in the nucleus
2. nucleus is in the nucleus
3. electron cloud is in the electron cloud
4. positively charged particles (protons) are in the nucleus
5. negatively charged particles (electrons) are in the electron cloud
Current = (voltage) / (resistance)
= (35 volts) / (1,400 ohms)
= 25 milliamperes