Answer:
Distance of closest approach, 
Explanation:
It is given that,
Charge on proton, 
Charge on alpha particle, 
Mass of proton, 
Mass of alpha particle, 
The distance of closest approach for two charged particle is given by :



So, their distance of closest approach, as measured between their centers
. Hence, this is the required solution.
in case you dont want to read the answer is B
Answer:
satellites and weather fronts