One sample t-test, for testing population mean to a specified value $(\mu_0)$ is given by :

$t=\frac{\overline{x}-\mu_0}{S/\sqrt{n}}$

The correct answer is Option (2) → $t=\frac{\overline{x}-\mu_0}{S/\sqrt{n}}$

The test statistic for the one-sample,

$t=\frac{\overline{x}-\mu_0}{S/\sqrt{n}}$

where,

$\bar x$ = Sample mean

$\mu_0$ = Specified population mean

$s$ = Sample standard deviation

$n$ = Sample size