Abbie, age 30, is the sole owner and only employee of Pink, Inc., an S-Corporation. Abbie decides to open a Traditional Solo 401(k) plan to shelter some of her $75,000 in W-2 earnings from income tax. As an owner and an employee of her company, what is the total amount that can be contributed on a pre-tax basis to her Traditional Solo 401(k) plan in 2021?

1. $19,500
2. $18,750
3. $38,250
4. $58,000