Sudoku types for month

There will be 4 Classic Sudokus in Round1.
The variations in Round2 in this month are Trio Sudoku, Odd Even Sudoku, Alphabet Sudoku and Diagonal Sudoku.
Rules and examples are provided below.

Classic Sudoku

Place the digits 1 through 9 into the empty cells in the grid so that each digit appears exactly once in each of the rows, columns, and bold outlined 3X3 boxes.

Answer key for the above Sudoku is : 416978325, 327186459

Trio Sudoku

Apply Classic Sudoku rules. Some cells will have circles inside and some others will have squares. Cells with circles must contain the digits 1, 2 and 3. Cells with squares must contain the 4, 5 and 6. Blank cells must contain the digits 7, 8 and 9.

Answer key for the above Sudoku is : 429876315, 562498173

Odd Even Sudoku

Apply Classic Sudoku rules. All shaded cells must contain even digits. All white cells must contain odd digits.

Answer key for the above Sudoku is : 243978156, 982765431

Alphabet Sudoku

Place the letters A through I into the empty cells in the grid so that each letter appears exactly once in each of the rows, columns, and bold outlined 3X3 boxes.

Answer key for the above Sudoku is : DAFIGHCBE, CBGAHFEI

Diagonal Sudoku

Place the digits 1 through 9 into the empty cells in the grid so that each digit appears exactly once in each of the rows, columns, bold outlined 3X3 boxes, and every diagonal marked by lines.

Answer key for the above Sudoku is : 243978156, 982765431