20. Choose the sentence with the correct punctuation:
(1 Point)
a. Sid, and Sam, who had been friends for years, went on vacation together every summer
b. Sid, and Sam, who had been friends for years, went on vacation together, every summer.
c. Sid and Sam who had been friends for years went on vacation together, every summer!
d. Sid and Sam, who had been friends for years, went on vacation together every summer.