Given the task definition and input, reply with output. In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Question: How many copies did Strout's sequel to Olive Kitteridge sell? Passage:Strout's first novel, Amy and Isabelle (1998) met with widespread critical acclaim, became a national bestseller, and was adapted into a movie starring Elisabeth Shue. Her second novel, Abide with Me (2006), received critical acclaim but ultimately failed to be recognized to the extent of her debut novel. Two years later, Strout wrote and published Olive Kitteridge (2008), to critical and commercial success grossing nearly $25 million with over one million copies sold as of May 2017. The novel won the 2009 Pulitzer Prize for Fiction. The book was adapted into a multi Emmy Award-winning mini series and became a New York Times bestseller. Five years later, she published The Burgess Boys (2013), which became a national bestseller. My Name Is Lucy Barton (2016) was met with international acclaim and topped the New York Times bestseller list. Lucy Barton later became the main character in Strout's 2017 novel, Anything is Possible. A sequel to Olive Kitteridge, titled Olive, Again, was published in 2019.
Links: a. Olive, Again b. The Burgess Boys c. My Name Is Lucy Barton d. Abide with Me (novel)
a