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

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

A$)E+S+L+B3$

B$)3E+3S+3L+3B12$

I $E+L+B3$

D$)E+S+L+B4$

A$.$ A

B$.$ B

C$.$ C

D$.$ D