What's the lowest score in the English grading test for freshmen in Southwest University?
2a. Southwest University located in Chongqing, referred to as Xida for short, is a university directly under the Ministry of Education of People's Republic of China (PRC), which is jointly established by the Ministry of Education, the Ministry of Agriculture and Rural Affairs and the Chongqing Municipal People's Government. The scores of freshmen's English test in this school are 2a, 2b, 2c, 1a, 1b, 1c, 1d respectively. Grading test is only a reflection of English level.