（單選）Given a list of binary trees $T = \{t_1, t_2, \ldots, t_7\}$ where each node is 0 or 1 shown as below, we would like to insert these trees into a linear-probing hash table of length $N = 11$. The hash function $f(t) = g(h(t)) \bmod N$, where $h(t)$ is the binary sequence obtained from in-order traversal of tree $t$ and $g(\cdot)$ converts a binary sequence to a decimal number. For instance, $g(\text{"1111111"}) = 127$. Here's the question: how many collisions occur during the insertion process?