Detailed Instructions: 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.
Problem:Question: In what year was the lower jaw of an Anachlysicitis found in the Vilavieja Formation? Passage:Anachlysictis gracilis is an extinct carnivorous mammal belonging to the group Sparassodonta, which were metatherians (a group including marsupials and their close relatives) that inhabited South America during the Cenozoic. Unlike other remains assigned to the family Thylacosmilidae (a group of metatherian predators equipped with "saber teeth") that had been found previously, Anachlysictis is the first record of such borhyaenoids in northern South America, and also most primitive and ancient in the family (in fact, is the first confirmed record that did not belong to the genus Thylacosmilus, until the official publication of Patagosmilus in 2010). This species was found in the Villavieja Formation in the area of La Venta in Colombia, a famous fossil deposit in the Middle Miocene (Laventan; 13.8-11.8 million years ago), based on fragments that include a front portion of the lower jaw, with an incipient molar tooth and a piece of carnassial from the front of the maxilla.
 Links: a. Patagosmilus b. South America c. Thylacosmilidae d. Colombia
Solution:
a