The word “oil” originally means “any kind of smooth greasy liquid” but later acquires the specific meaning of “petroleum”.This word-forming method is called（）.

The word “oil” originally means “any kind of smooth greasy liquid” but later acquires the specific meaning of “petroleum”.This word-forming method is called（）.
A.Specialization
B.Specification
C.Generalization
D.Extension
正确答案：Specialization