A grid of 6x6 squares is shown. Some squares are colored green, and the rest are colored white. Determine the difference between the number of green squares and white squares, and select the correct o

Count the green squares row by row from top to bottom:
Row 1: 1 green square
Row 2: 2 green squares
Row 3: 3 green squares
Row 4: 4 green squares
Row 5: 5 green squares
Row 6: 6 green squares
Total green squares $= 1 + 2 + 3 + 4 + 5 + 6 = 21$.

Count the white squares row by row from top to bottom:
Row 1: 0 white squares
Row 2: 1 white square
Row 3: 2 white squares
Row 4: 3 white squares
Row 5: 4 white squares
Row 6: 5 white squares
Total white squares $= 0 + 1 + 2 + 3 + 4 + 5 = 15$.

Difference $= \text{Number of green squares} - \text{Number of white squares}$

The calculated difference is 6. This matches option (C).

The final answer is $\text{C) 6}$.