`P` and `Q` are isomers of dicarboxylic acid `C_(4)H_(4)O_(4)`. Bothdecolorize `Br_(2)//H_(2)O`. On heating, `P` forms the cyclic anhydride. Upon treatment with dilute alkaline `KMnO_(4),P` as well as `Q` could produce one or more than one forms `S,T` and `U`.

Compounds formed from `P` and `Q` are, respectively
A. Optically active S and optically active pair (T,U)
B. Optically inactive S and optically inactive pair (T,U)
C. Optically acitve pair (T,U) and optically acitve S
D. Optically inactive pair (T,U) and optically inactive S.