Determine the effects of the following on a cash basis taxpayer’s gross income for 2019 and 2020:

a. On the morning of December 31, 2019, the taxpayer received a $1,500 check from a customer. The taxpayer did not cash the check until January 3, 2020.

b. The same as part (a), except that the customer asked the taxpayer not to cash the check until January 3, 2020, after the customer’s salary check could be deposited.

c. The same as part (a), except that the check was not received until after the bank had closed on December 31, 2019.