Step 1: Recall what the diagram plots.
The figure is a climate classification chart with mean annual temperature on the vertical axis and mean annual precipitation on the horizontal axis. Each labelled field on such a chart marks out a combination of temperature and rainfall that defines a named climate zone, and this scheme is widely used in climatic geomorphology to relate climate to the dominant surface processes.
Step 2: Read the position of zone P.
Zone P sits at the bottom left of the chart, covering a wide range of temperature that dips well below \(0^{\circ}C\), together with very low precipitation, under about \(50\) cm a year. Cold temperatures combined with very little rainfall describe a glacial climate, where moisture is often locked as ice rather than falling as rain.
Step 3: Read the position of zone Q.
Zone Q sits at the top left, with high temperature, around \(25\) to \(35^{\circ}C\), but still very low precipitation, again under about \(50\) cm a year. Hot conditions with almost no rainfall is the signature of an arid or hot desert climate.
Step 4: Read the position of zone R.
Zone R lies in the upper middle part of the chart, at moderately high temperature with precipitation in the range of roughly \(50\) to \(150\) cm a year, more than zone Q but still well short of the wettest part of the chart. This intermediate rainfall at warm temperature marks a semiarid or steppe climate, a transitional zone between true desert and wetter climates.
Step 5: Read the position of zone S.
Zone S occupies the right hand side of the chart, spanning a wide temperature range but always paired with high precipitation, from about \(200\) cm up to over \(300\) cm a year. Warm to hot temperature together with heavy year round rainfall is characteristic of a tropical climate.
Step 6: Assemble the match and check the options.
This gives P as Glacial, Q as Arid, R as Semiarid, and S as Tropical.
(A) P-Glacial; Q-Arid; R-Tropical; S-Semiarid: Gets P and Q right but swaps R and S. Incorrect.
(B) P-Arid; Q-Semiarid; R-Tropical; S-Glacial: Shifts every label by one position around the chart. Incorrect.
(C) P-Glacial; Q-Arid; R-Semiarid; S-Tropical: Matches our reading of the chart exactly. Correct.
(D) P-Tropical; Q-Arid; R-Semiarid; S-Glacial: Swaps P and S, putting the coldest zone as tropical and the wettest zone as glacial. Incorrect.
Step 7: Final conclusion.
\[
\boxed{P\text{-Glacial; }Q\text{-Arid; }R\text{-Semiarid; }S\text{-Tropical}}
\]
Hence, the correct option is (C).
