Multiple choice: show how got answer

Dallas Corporation wishes to market a new product for $1.50 a unit. Fixed costs to manufacture this Product are $100,000 for less than 500,000 units OR $150,000 for 500,000 OR MORE units. The contribution margin is 20%. How many units must be sold to realize at least net income of $100,000 from this product ?

A) 333,333 units

B) 500,000 units

C) 666,667 units

D) 833,333 units