Use reference angles to find the exact value of the following expression. Do not use a calculator. \( \sin \left(-300^{\circ}\right) \) Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. \( \sin \left(-300^{\circ}\right)=\square \) (Simplify your answer. Type an exact answer, using radicals as needed. Use integers or fractions for any numbers in the the denominator.) B. The answer is undefined.

To find \( \sin \left(-300^{\circ}\right) \), we first need to find the reference angle. Since \(-300^{\circ}\) is a negative angle, we can convert it to a positive angle by adding \(360^{\circ}\): \[ -300^{\circ} + 360^{\circ} = 60^{\circ} \] The reference angle is \(60^{\circ}\). Now, since we are looking for \(\sin\) of a negative angle, we use the property that \(\sin(-\theta) = -\sin(\theta)\): \[ \sin \left(-300^{\circ}\right) = -\sin(60^{\circ}) \] The sine of \(60^{\circ}\) is \(\frac{\sqrt{3}}{2}\). Therefore: \[ \sin \left(-300^{\circ}\right) = -\frac{\sqrt{3}}{2} \] So, the answer is: A. \( \sin \left(-300^{\circ}\right) = -\frac{\sqrt{3}}{2} \)