What major should I put on my app?

Actually, at many colleges, CS is the more competitive major to get admitted to, and change into once you are in college. You need to check carefully for each college which major, if any, is a more competitive or selective major.

Note that if you apply to a less competitive or selective major, get admitted, and enroll at the college, you may not be able to change into the more competitive or selective major later.

http://talk.qa.collegeconfidential.com/college-admissions/1947599-faq-does-intended-major-make-it-easier-or-more-difficult-to-get-into-a-college.html