Panel I below shows a grid of cells with four rows and four columns. The numbers on the top of each column and on the left of each row tell us how many cells in that column or row must be shaded. The column totals, left to right, are 2, 2, 2, 2, and the row totals, top to bottom, are 3, 1, 2, 2. Panel II below shows four candidate grids, labelled (i) to (iv), with some cells shaded grey.
Which one of the options shown in Panel II represents the grid shaded correctly?