Final answer:
A defendant who stands mute at an arraignment is considered to have entered a not-guilty plea, with the court entering the plea to prevent legal process delays. So, the correct answer is option a.
Step-by-step explanation:
When a defendant 'stands mute' at her arraignment, she is considered to have entered a not-guilty plea. Standing mute means that the defendant chooses not to speak or enter a plea. In such cases, the court typically enters a not-guilty plea on the defendant's behalf to allow the legal process to continue.
It is essential for the justice system to keep moving forward, so this act safeguards against delays in court proceedings. Defendants also maintain their rights when standing mute, including the right to remain silent and avoid self-incrimination, as protected under the Fifth Amendment.