The plastic strain ratio is defined as the _______________ (where Wi, Wf is initial and final width of work piece, Li, Lf is initial and final length of work piece).

The plastic strain ratio is defined as the _______________ (where Wi,

1.	The plastic strain ratio is defined as the _______________ (where Wi, Wf is initial and final width of work piece, Li, Lf is initial and final length of work piece).
A.	ln(Wi/Wf)
B.	ln(Wi/Wf)/ln(Li/Lf)
C.	ln(Wi/Wf)/ln(LfWf/LiLf)
D.	ln[(Wi/Wf)/(LfWf/LiLf)]
Answer» D.