In the options given election has a lowest charge.

Electron < Proton < He⁺ <Li⁺⁺

Formula used: The magnetic force is given by

Where F is magnetic force

q is electric charge =

v is velocity

m is mass of the charge particle

v is velocity

r is radius of the projectile motion

Here v and B are constants and q is same for all the charge particles. r is proportional to m. If radius is small radius will become small. Electron exhibits light weight among the all other charge particles. Because of light weight it will creates a circle with a small radius when it is projected. So option A is correct.