Saba conducts regular tours of his favorite city in the world, Paris. Each semester he selects among the finest students in the university and escorts them to the City of Lights. In addition to a world-class education on conducting business in Europe, he arranges a number of cultural outings for them to help them immerse themselves in all that France has to offer. He collects an extra $100 from each student for this purpose and limits his tour group to ten lucky individuals. Some of the events (and their prices) he proposes to the students include:

Eiffel Tower visit, $40 per student, E
Paris Sewer spelunking, $20 per student, S
Half day passes to the Louvre, $60 per student, L
Bon Beret tour, $50 per student, B

So much to do and so little time!

Which constraint is most appropriate if the students can choose only three of these activities?

A. E + S + L + B ≤ 4
B. E + S + L + B ≥ 2
C. $40E + $20S + $60L + $50B ≤ $100
D. E + S + L + B ≤ 3