1. Basicity depends on availability of the lone pair on nitrogen for donation to a proton.

2. Piperidine:

   • Piperidine is a saturated aliphatic amine.
   • The lone pair on nitrogen is localized and easily available for protonation.
   • Hence, it is strongly basic.

3. Pyridine:

   • In pyridine, nitrogen is $sp^2$ hybridized.
   • Its lone pair lies in an $sp^2$ orbital and is not involved in the aromatic sextet.
   • So it is available for protonation, but due to greater $s$-character of $sp^2$ orbital, it is held more tightly than in piperidine.
   • Therefore, pyridine is less basic than piperidine.

4. Pyrrole:

   • In pyrrole, the lone pair on nitrogen is part of the aromatic sextet.
   • If this lone pair is donated to a proton, aromaticity is lost.
   • Therefore, the lone pair is least available for protonation.
   • Hence, pyrrole is very weakly basic.

5. Therefore, the correct order of basic strength is $\text{Piperidine} > \text{Pyridine} > \text{Pyrrole}$

6. Checking options:

   • A: $\text{Pyridine} > \text{Piperidine} > \text{Pyrrole}$ ❌
   • B: $\text{Pyrrole} > \text{Piperidine} > \text{Pyridine}$ ❌
   • C: $\text{Pyrrole} > \text{Pyridine} > \text{Piperidine}$ ❌
   • D: $\text{Piperidine} > \text{Pyridine} > \text{Pyrrole}$ ✅

So, the correct answer is D.