A curve C is given by a vector function $\mathbf{r}(t), 2 \leq t \leq 7$, with unit tangent $\mathbf{T}(t)$, unit normal $\mathbf{N}(t)$, and unit binormal $\mathbf{B}(t)$. Indicate whether the following line integrals are positive, negative, or zero by typing P, N, or Z as appropriate:

A. $\int_C \mathbf T \cdot \, d\mathbf r =$

B. $\int_C \mathbf N \cdot \, d\mathbf r =$

C. $\int_C \mathbf B \cdot \, d\mathbf r =$