Select the dice that can be formed by folding the given sheet along the lines.

When the sheet is folded,

3 is opposite to 2

1 is opposite to 4

6 is opposite to 5

From the dice B, 6 is not opposite to 5. Hence dice B cannot be formed.

From the dice C, 3 is not opposite to 2. Hence dice C cannot be formed.

From the dice D, 1 is not opposite to 4. Hence dice D cannot be formed.

When the sheet is folded by keeping 6 at top position, 1 will be left of 3 similarly as shown in dice A. So dice A can be formed.

$$\therefore\ $$Only dice A can be formed by folding the given sheet.

Hence, the correct answer is Option B