Negative montoux test is when induration is -

Ans. is 'a' i.e., < 5 mm MethodIntradermal injection of PPD on flexor aspect of forearm|Examined at 48-72 hours||||Induration > 10 mmInduration < 5 mmInduration 6-9 mm|||PositiveNegativeEquivocal|Repeat tuberculin test (two step testing)