Direction: In the following question there is a sentence of which some parts have been jumbled up. You are required to rearrange these parts which are labeled P, Q, R and S, to produce the correct sentence. Choose the correct sequence.

P. by an emperor named Shahjahan

Q. the Taj Mahal is a

R. in memory of his wife Mumtaz Mahal

S. beautiful monument built in 1631.