Which of the following is the equation involved in window to viewport mapping(symbols have their usual meanings)

Which of the following is the equation involved in window to viewport

1.	Which of the following is the equation involved in window to viewport mapping(symbols have their usual meanings)
A.	xv=sxxw+tx,yv=syyw+ty
B.	xv=sxxw-tx,yv=syyw-ty
C.	xv+sxxw=tx,yv+syyw=ty
D.	xv=sxxwtx,yv=syywty
Answer» B. xv=sxxw-tx,yv=syyw-ty