Please show and explain how the correct answer is 300 for the first part and 2100 for the second part. thank you!

Joe's Cross Fit, an accrual-method taxpayer, provides personal training services. On September 30, 2019, Barbie pays Joe's Cross Fit $2,400 cash for 24 months of personal training services ($100/month). Barbie's training sessions beginning on October 1, 2019. For book purposes, Joe's Cross Fit will recognize $300 in income in 2019, $1,200 in 2020, and $900 in 2021. For tax purposes, how much of the $2,400 must Joe's Cross Fit include in gross income in 2019 if Joe's elects to defer prepaid income to the maximum extent possible? ered 2,400 swers 300 (with margin: 0) 0/0.3 pts Question 14 Same facts as previous question. For tax purposes, how much of the $2,400 must Joe's Cross Fit include in gross income in 2020? ered 0 swers 2,100 (with margin: 0)