Andrew is going to use the "debt snowball" method to tackle his outstanding debt. Based on this method, which debt should he pay off first?
1) His auto loan with a $2,700 outstanding balance and 2.99% interest rate
2) His Southwest Airlines credit card with a $4,200 outstanding balance and 19.9% interest rate
3) His student loans with a $22,000 outstanding balance and 5.5% interest rate
4) His home mortgage with a $277,000 outstanding balance and a 6.75% interest rate