A person is considered to be what if they understand the nature and effect of their deed?

A person is considered mentally competent if they can understand the nature and effect of their actions, particularly in legal contexts. This understanding includes the ability to grasp what a deed entails and the implications of that deed. Mental competence is a fundamental requirement for individuals to engage in legally binding agreements or transactions. It ensures that they can make informed decisions and are aware of the responsibilities and consequences that arise from their choices.

In contrast, other classifications such as legally incompetent would suggest a lack of understanding, while being under duress refers to acting under pressure or coercion, which can impair judgment. Misguided typically implies a lack of correct guidance rather than an inability to understand one's actions. Therefore, mental competence directly correlates with the understanding of the nature and effects of one's deeds, confirming that the correct choice accurately reflects this legal principle.