Nitration of aniline in strong acidic medium also gives $\mathrm{m}$-nitroaniline because:

• A

  In absence of substituents nitro group always goes to $\mathrm{m}$-position.
• B

  In electrophilic substitution reactions amino group is meta directive.
• C

  In spite of substituents nitro group always goes to only $\mathrm{m}$-position.
• Correct answer
  D

  In acidic (strong) medium aniline is present as anilinium ion.

Solution

In acidic medium aniline is protonated to form anilinium ion which is metadirecting (due to $+\mathrm{I}$ effect).

Hence, the correct answer is option: 'D'.