Marcia is a graphic designer. She took a series of courses on basic coding and used what she learned to solve a big problem for the team. In doing so, she demonstrated

Competence

Explanation: Competence is showcased when an individual demonstrates a reasonable level of expertise in a particular art enabling such person to perform efficiently. In the scenario above, Marcia could be described as being competent as she was able to put her acquired coding skill to use while solving a real world problem. Learning a skill or various skills doesn't define competence, however, the ability to put such skills into real world usage defines the level of competence of such individual.

the answer to your question is,

d. when a child was born.

-mabel < 3