Sudoku puzzle is a 99 square that is divided into nine 33 sub squares. A solution of Sudoku puzzle is a configuration in which each row, column, and sub square contains each integer number from [1, 9] once and only once. A starting point of the Sudoku puzzle is shown below. A. Discuss the environment of Sudoku puzzle. [Fully/partially observable? Deterministic or not?] B. How many possible combinations are there in one EMPTY SUB SQUARE (33 square) under the condition that each sub square contains a unique integer from [1,9]? C. List one search algorithm that you think suitable for solving the Sudoku puzzle and why