which has highest e/m ratio

1 .He2+

2.H+

3.He+

4.H

e / m ratio is charge by mass ratio. Option (B) is right
For H⁺ charge is 1 and mass is also 1, so ratio is 1.
For He²⁺, charge is 2 and mass is 4, so ratio will be 0.5.
For He^+, charge is 1 and mass is 4 ,so ratio will be 0.25