Orientation: rows first

A 2D array is an array of rows. int[][] g = new int[3][4] is 3 rows of 4 columns; g.length is 3 (rows), g[0].length is 4 (columns). The single most reliable exam fact: g[r][c] — row first, always.

Row-major traversal (the natural order):

for (int r = 0; r < g.length; r++) {
    for (int c = 0; c < g[r].length; c++) {
        // g[r][c]
    }
}

Inner bound g[r].length (not g[0].length) is the exam-safe form — it works even if rows had different lengths, and it is what the reference solutions accept.

Column traversal — outer loop over columns, inner over rows:

for (int c = 0; c < g[0].length; c++) {
    for (int r = 0; r < g.length; r++) {
        // g[r][c] — walks DOWN one column
    }
}

Position vocabulary for {1,2,3},{4,5,6}: g[0] is the FIRST row (1,2,3); g[2][0] is row index 2, column 0 → value 6... no — check: { {1,2,3}, {4,5,6} } has 2 rows; g[1][0] is 4. Draw the grid with indexes labeled before answering anything. Every wrong "which element" MCQ comes from row/column transposition.