The order of  stability of the following free radicals is

(A)

 

 

 

(B)

 

 

 

 

 

 

(C)

 

 

 

(D)

B - Benzyl free radical…most stable due to resonance.

A - Secondary free radical….6 $\mathrm{\alpha }$-hydrogens…Hyper conjugation

D - Primary free radical….. 3 $\mathrm{\alpha }$- H atoms….Hyper conjugation

C - Primary free radical…..1 $\mathrm{\alpha }$ - H atom….Hyper conjugation