Directions: Each of the following items in this section consists of a sentence, parts of which have been jumbled. These parts have been labelled as P, Q, R and S. Given below each sentence are four sequences, namely (a), (b), (c) and (d). You are required to re-arrange the jumbled parts of the sentence and mark your response accordingly.

(P) which is composed of iron and nickel / (Q) a molten core is found / (R) at the heart of the Earth, / (S) and generates the planet's magnetic field.