All three choices are correct.
Answer:

Explanation:
As we know that
velocity of bike = 7.5 m/s
velocity of car is 10 m/s
deceleration of car is 0.75 m/s^2
part a)
velocity of bike with respect to car is given as

acceleration of bike with respect to car is given as

now the distance of the bike with respect to car is given as



Part b)
The correct answer is C) becuse without certain medicine they will dieeeee
Electric field due to a point charge is given as

here we know that

also the distance is given as

now we will have

so we will have

so above is the electric field due to proton
It traveled 200 m in 50 seconds. 200/50 can be simplified to 4 m/s!
The velocity is -4 m/s (negative because it travelled from 100 to -100 or backwards)