Which sentence correctly uses punctuation to separate coordinating adjectives?

1. Senator Wiggins chose the most competent intelligent applicant for the prestigious, summer internship.

2. Senator Wiggins chose the most competent, intelligent, applicant for the prestigious summer internship.

3. Senator Wiggins chose the most, competent intelligent, applicant for the prestigious summer internship.

4. Senator Wiggins chose the most competent, intelligent applicant for the prestigious summer internship.