For one month, a business has fixed costs of $\$150\,000$. Its only product is sold at $\$20$ per unit, and the contribution to sales ratio is $75\%$. It wants to earn a profit of $\$300\,000$ in that month. How many units must the business sell?
- A$10\,000$
- B$20\,000$
- C$22\,500$
- D$30\,000$