Which of the following choices CORRECTLY punctuates this sentence with commas?

When Micah attended the Broadway show with his only sister Megan they sat in the front row.
a.
When Micah attended the Broadway show, with his only sister, Megan, they sat in the front row.
c.
The sentence is correct.
b.
When Micah attended the Broadway show with his only sister, Megan, they sat in the front row.

Please select the best answer from the choices provided

A
B
C