The economy of Ireland has been traditionally agricultural, but

The economy of Ireland has been traditionally agricultural, but since ______ the country's industrial base has expanded.
A、the mid-1950s
B、the mid-1960s
C、the 1970s
D、the 1980s
【正确答案】：A
【题目解析】：爱尔兰的经济传统上是农业，但自20世纪50年代中期以来，该国的工业基础已经扩大。