Directions: Each of the following items in this section consists of a sentence, the parts of which have been jumbled. These parts have been labelled 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 correctly and mark your response accordingly.

Has been challenged (P) / the notion is that (Q) / by recent discoveries (R) / humankind (S)