I think C is the correct answer
The teacher usually ask different questions, but if you have the questions then i can help :)
Answer:
"Because the particles (electrons and ions) in a plasma have an electrical charge, the motions and behaviors of plasmas are affected by electrical and magnetic fields. ... Ions have a positive electrical charge because they have more positively charged protons than negatively charged electrons."
-Educationscied.ucar.edu › plasma
So what you got to do is divide them perseay use a calculator for the first one 2/15 what would that be in a decimal 0.13333333333333 what ever on has 0.13333333 or something else repeating that is the one that you will circle 11/20=0.55 17/40 =0.425 1/2=0.5 so you answer would be 2/15
hope this helped