KC=9 for the reaction,  A + B   ⇌   C +  D.  If  A and B are taken in equal amounts, then amount of C in equilibrium is

A    +     B   ⇌   C    +    DInitial                     1           1           0           0At equilibrium     (1 - x)    (1 - x)      x           x∴       KC =  C  DA B=9∴     x. x1 - x2= 9or      x2  = 9  +  9x2  -  18xor      8x2  - 18x  +  9  =  0∴   x = 32   or     34Hence, among the given options, option (c), i.e., 0.75 is correct.