Evaluate the trigonometric function at the quadrantal angle, or state that the expression is undefined. \( \cot \pi \) Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. \( \cot \pi=\square \) B. The expression is undefined.

To evaluate \( \cot \pi \), we first recall the definition of the cotangent function: \[ \cot \theta = \frac{\cos \theta}{\sin \theta} \] Now, we can find the values of \( \cos \pi \) and \( \sin \pi \): \[ \cos \pi = -1 \] \[ \sin \pi = 0 \] Substituting these values into the cotangent function gives: \[ \cot \pi = \frac{\cos \pi}{\sin \pi} = \frac{-1}{0} \] Since division by zero is undefined, we conclude that: \[ \cot \pi \text{ is undefined.} \] Thus, the correct choice is: B. The expression is undefined.