Based on the following passage on construction technology during the Middle Ages, why might a worker not be allowed to join a guild? During the Middle Ages, a family worked in a trade for generations, with fathers training sons and passing knowledge along bloodlines.
Masons learned how to carve elaborate gargoyles; glaziers made intricate stained-glass windows. These skilled workers were organized into
guilds, and on a construction site, guild workers were highly esteemed while lower-level unskilled workers completed simple routine tasks.
All laborers were paid.

He did not pass the necessary exams to qualify for guild membership

He had signed a contract forgoing payment in exchange for on-the-job training.

He was not born into a family of skilled laborers

His specialty did not fall under masonry or glazing.