Derek, age 28, files single. On April 10, 2020, he filed for an automatic six-month extension to file his tax return. Three weeks later, on May 5, he timely filed his 2019 tax return. What is the latest date on which he is eligible to make a 2019 contribution to an IRA?

(a) December 31, 2019.

(b) April 15, 2020.

(c) May 5, 2020.

(d) October 15, 2020.