A.\(\left\{ {a;\,\,b} \right\},\,\,\left\{ {a;\,\,3} \right\},\,\,\left\{ {a;\,\,7} \right\},\,\,\left\{ {b;\,\,3} \right\},\,\,\left\{ {3;\,\,7} \right\}\).
B.\(\left\{ {a;\,\,b} \right\},\,\,\left\{ {a;\,\,3} \right\},\,\,\left\{ {a;\,\,7} \right\},\,\,\left\{ {b;\,\,3} \right\},\,\,\left\{ {b,7} \right\},\,\,\left\{ {3;\,\,7} \right\}\).
C.\(\left\{ {a;\,\,b} \right\},\,\,\left\{ {a;\,\,3} \right\},\,\,\left\{ {a;\,\,7} \right\},\,\,\left\{ {b,7} \right\},\,\,\left\{ {3;\,\,7} \right\}\).
D.\(\left\{ {a;\,\,b} \right\},\,\,\left\{ {a;\,\,3} \right\},\,\,\left\{ {b;\,\,3} \right\},\,\,\left\{ {b,7} \right\},\,\,\left\{ {3;\,\,7} \right\}\).