7.82 The graph of the function that is symmetric to the graph of $y=f(x-a)+b$ with respect to the line $y=x$ is
(A) $y=f^{-1}(x-a)+b$.
(B) $y=f^{-1}(x+a)-b$.
(C) $y=f^{-1}(x-b)+a$.
(D) $y=f^{-1}(x-b)-a$.
(China Beijing High School Mathematics Competition, 1992)