Communications, Arts and Sciences or Exploratory Studies

My son is really interested in CU Boulder but is somewhat undecided - leaning towards the majors offer in the Communications school. If he is open to the school that he gets in to, what is best school to apply for to increase his chances of getting in? I understand Exploratory Studies is relatively new and is essentially for undecided students.

The Engineering school is very competitive and the business school is slightly competitive. The rest of the University is manageable.

What are his stats?