Kyle and Elena Smith contributed to the support of their two children, Alexandra and Matthew, and Elena’s divorced father Nick. This year, Alexandra, age 22 and a full-time college student, earned $1,700 from a part-time job. Matthew, age 27 and a full-time graduate student, earned $23,000 from his job as a teaching assistant. Nick received $12,000 in capital gains income and $7,000 in nontaxable Social Security benefits. Alexandra, Matthew, and Nick are U.S. citizens; more than half of their support was provided by Kyle and Elena. How many exemptions can Kyle and Elena claim on their joint income tax return?

a. 2

b. 3

c. 4

d. 5