A Country Has 50 Million People, 30 Million of Whom

A country has 50 million people, 30 million of whom are adults. Of the adults, 5 million are not interested in working, another 5 million are interested in working but have given up looking for work, and 5 million are still looking for work. Of those who do have jobs, 5 million are working part time but would like to work full time, and the remaining 10 million are working full time. How many discouraged workers does this country have?

A) 5 million
B) 10 million
C) 15 million
D) 20 million