Which sentence uses punctuation correctly?
a. My father's best friend from college, Sheriff Redmond Whitman is also a cattle rancher.
b. My father's best friend from college Sheriff Redmond Whitman, is also a cattle rancher.
c. My father's best friend from college, Sheriff Redmond Whitman, is also a cattle rancher.
d. My father's best friend from college Sheriff Redmond Whitman is also a cattle rancher.