How many personal exemptions can be claimed. Income tax return.?

The Hutters filed a joint return for 2010. They provide more than 50% of the support of Carla, Melvin, and Aaron. Carla (age 18) is a cousin and earns $5,000 from a part-time job. Melvin (age 25) is their son and is a full-time law student. He received from the university a $3,800 scholarship for tuition. Aaron is a brother who is a citizen of Israel but resides in France. Carla and Melvin live with the Hutters. How many personal and dependency exemptions can the Hutters claim on their Federal income tax return?