Rearrange the following parts of a sentence in order to make a meaningful sentence:
P. for five years, I was sure
Q. when I decided to go abroad
R. that my grandmother would be upset
S. and at her age one could never tell

Part Q establishes the timeframe of the sentence and is likely the opening portion. If R follows Q, the justification for the grandmother's upset is lacking, whereas if S follows Q, there is no noun for 'her' to refer back to; the only portion that can follow Q is P. After P, we come to recognise that the reason for the grandmother being upset must be the person going abroad for 5 years. Lastly, S can conclude with the pronoun 'her' referring back to the author's grandmother. The sequence should be QPRS. Option D is the correct answer.