Whenever a person indicted stands mute or refuses to plead, the court shall order the plea of not guilty to be entered, and it shall have the same effect as if the accused had pleaded not guilty.
N.H. Rev. Stat. Ann. § 605:5
Refusal to Plead
Source
Official source: New Hampshire General Court. Reproduced from public-domain New Hampshire statutes; confirm against the official source for the current text. Not legal advice.