Why do airlines often charge students and vacationers a lower price than busines travelers?

A. It is cheaper to provided airline service to students and vacationers than to business travelers.

B. The demand of business travelers is generally more elastic than the demand of students and vacationers.

C. The demand of students and vacationers is generally more elastic than the demand of business travelers.

D. Airlines prefer to deal with students and vacationers rather than business travelers.

For answers to both your price discrimination questions see the diagram on http://www.revisionguru.co.uk/economics/...
at the bottom of the page on third degree price discrimination. It is to do with differing elasticity in both markets. Here students have a more elastic demand curve, so the airline can charge them a lower price to encourage them to fly more, while being able to pick them out from business travelers who have to fly, therefore have a more inelastic demand curve and as such the airline can afford to charge them more.