A company collects 70% of its sales during the month of sale, 20% one month after the sale, and 10% two months after the sale. The company expects sales of $20,000 in September, $30,000 in October, $40,000 in November, and $50,000 in December. How much money is expected to be collected in November?

a) $28,000

b) $24,000

c) $36,000

d) $46,000