The amino group when attached to the ring makes it highly activating towards electrophilic substitution. Consequently, the electrophilic substitution

The amino group when attached to the ring makes it highly activating towards electrophilic substitution. Consequently, the electrophilic substitution readily takes place in aniline at all the three ortho and para positions. However on acetylation with acetyl chloride the activation of the ring to amino group is sufficiently reduced and the electrophilic substitution in benzene ring takes place preferably at the para position which is less hindered than the ortho position.
Towards electrophilic substitution, most reactive will be
A. Nitrobenzene
B. Aniline
C. Aniline hydrochloride
D. N acetylamine.