Neco Model Questions Vol1 2018 Geography Question 41

Region X, Y and Z have the following average annual temperatures and monthly precipitation (in mm):\n\nRegion X: average temperature \(26^{\circ}\!C\); monthly precipitation: Jan 120, Feb 110, Mar 100, Apr 90, May 80, Jun 70, Jul 80, Aug 90, Sep 100, Oct 110, Nov 120, Dec 130.\nRegion Y: average temperature \(24^{\circ}\!C\); monthly precipitation: Jan 30, Feb 20, Mar 10, Apr 5, May 5, Jun 5, Jul 5, Aug 5, Sep 10, Oct 20, Nov 30, Dec 40.\nRegion Z: average temperature \(22^{\circ}\!C\); monthly precipitation: Jan 200, Feb 180, Mar 150, Apr 120, May 100, Jun 80, Jul 60, Aug 50, Sep 40, Oct 30, Nov 20, Dec 10.\n\nAccording to the Köppen climate classification, a region is classified as tropical savanna (Aw) if: (i) average annual temperature \(>18^{\circ}\!C\); (ii) the driest month has precipitation \(<60\) mm and also \(<100-\frac{\text{annual precipitation}}{25}\) mm. Which region is classified as tropical savanna (Aw)? Provide the region letter (X, Y or Z).