Lee Had Invested $100 000 in a Risk-Free Unit Trust

Lee had invested $100 000 in a risk-free unit trust, on which she earned $10 000 each year. She used that money to buy a prawn farm. She also quit her job as a salesperson to devote all of her time to her prawn business. Her salary as a salesperson was $25 000 per year.
-According to the information provided, what are Lee's opportunity costs of operating her new business?

A) $10 000
B) $25 000
C) $35 000
D) $50 000