Simplify the following text for a Grade 9 native English-speaking person.
Original: By enrollment , the three largest undergraduate units are the College of Literature , Science , and the Arts , the College of Engineering , and the Ross School of Business .
Simplified: About 65 % of undergraduate students go to the College of Literature , Science , and the Arts ( LS&A ) , while the College of Engineering has about 20 % . Less than 3 % of undergraduate students go to the Ross School of Business .