Mr. and Mrs. Vonce, both age sixty-two, filed a joint return for 2010. They provided all the support for their daughter, who is nineteen, legally blind, and who has no income. Their son, age twenty-one and a full-time student at a university, had $6,200 of income and provided 70% of his own support during 2010. How many exemptions should Mr. and Mrs. Vonce have claimed on their 2010 joint income tax return?

a. 2

b. 3

c. 4

d. 5