Final answer:
Huddie Ledbetter, known as Lead Belly, was part of the urban folk revival movement primarily due to his political activism. This was a common feature among musicians during the 1960s who used their art to address social and political issues.
Step-by-step explanation:
Huddie Ledbetter, more famously known as Lead Belly, was a key figure in the urban folk revival movement. He, alongside artists like Pete Seeger and Woody Guthrie, played an important role in this movement.
The correct answer to the student's question is a) Political activism.
Lead Belly joined this music-driven movement due to his political activism, which was echoed by many musicians of that era who used their music as a means to address social and political issues, such as the Civil Rights Movement and the Vietnam War.
Musicians like Bob Dylan and Leonard Cohen, while initially perhaps more focused on the artistic side of their work, eventually became known for their political leanings through their lyrics and the impact they had on society.
The involvement of artists in political activism during the 1960s was part of a larger cultural phenomenon where music, poetry, and other forms of art were utilized to express dissent, seek justice, and provoke change.
Therefore, Lead Belly's connection to the urban folk revival movement is most accurately attributed to his political activism rather than any engagement with mathematical prowess, expertise in chemistry, or proficiency in computer technology.