Which of the following is the correct order of ease of coupling with C₆H₅N₂Cl?
A) Benzene 
B) Nitro benzene
C) Phenol 
D) Chloro benzene

Presence of electron donating groups increases rate of coupling reactions 

-OH both +M and -I effect.+M > -I effect

-Cl only - I effect

-NO₂ both -M and -I and -M > -I effect

ordre : C>A>D>B