Reading ADF output

The notes report ADF statistics of −2.83 ($p = 0.055$) for the full monthly sample, −2.27 for 2001–2019 and −2.16 for 2010–2026. (a) Why is the $t$-statistic on $\gamma$ not compared with Student-$t$ critical values? What goes wrong if it is? (b) What is the correct conclusion for each sample at 5% and 10%? (c) The analyst tried three samples and two frequencies. How should that change the reading? (d) Suppose instead the analyst estimated $\ln G_t = \alpha + \beta\ln S_t + u_t$ by OLS and ran ADF on $\hat u_t$. Which critical values apply and why?