pH generally decreases across a period, with metal oxides generally forming basic oxides, semi-metals often forming amphoteric oxides and non-metals forming acidic oxides. However, this trend does not apply to the d-block metals, as the acidity of these metals is directly proportional to oxidation state (eg. CrO (containing Cr2+ ions) is basic, Cr2O3 (Cr3+) is amphoteric and CrO3 (Cr6+) is acidic).
I probably wouldn't include the thing about d block metals if the question was only worth two marks, but I can't think of anything else to add to make this an appropriate response for a four mark question.