A student tried to synthesis 4-nitro-N, N-dimethylaniline from N, N-dimethylaniline via electrophilic aromati substitution using nitric acid `(HNO_3)` and sulphuric acid `(H_2SO_4)`. To his surprice, the major product he obtained was 3-nitro-N, N-dimethylaniline. Why the disigned reaction failed to provide the desired product, 4-nitro-N, N-dimethylaniline?
A. The amine group is meta directing.
B. Protonation at amine group makes it meta directing.
C. The amine group is strong electron withdrawing group by -I effect.
D. Steric inhibition to resonance is responsible for the above result.
