Consider the following class declaration: class thing { private: int x; int y; static int z; public: thing() { x = y = z; } static void putthing(int a) { z = a; } }; int thing: : z = 0: assume a program containing the class declaration defines three thing objects with the following statement: thing one, two, three; a) how many separate instances of the x member exist? b) how many separate instances of the y member exist? c) how many separate instances of the z member exist? d) what value will be stored in the x and y members of each object?