The pair of particles which have same acceleration in a uniform electric field is

Concept Used: Relation between electric field, mass, charge and acceleration 

Detailed Solution:

qE = ma

a = qE /m 

Since a is directly proportional to q/ m 

$\text{ proton }\to \frac{1}{m_p}\text{. }$

Deutron $\to \frac{1}{2m_p}$

$\text{ proton -1/mp }$

$\text{ Alphaparticle →}\frac{2}{4m_p}=\frac{1}{2m_p}$

Hence the deuteron and alpha particle have same acceleration in uniform electric field.