For selection in worst-case linear time ambiguity in consideration of $n$ for which $T(n) =O(1)$ and $T(n)\leq cn$
It seems that $\dagger\dagger$ is consistent with $\|$. You just need to pick a constant $c$ that is larger than or equal to the constant $\gamma$ hidden in the $O(1)$ notation in the definition of $T(n)$ for $n &lt; 140$ (i.e., the line marked with $\ddagger$).
Then, for any $n \in \{1, \dots, 139\}$, you have $T(n) \le \gamma \le c \le cn$, as desired.