`S_(1)` : People have always been fascinated by dreams.
`S_(6)` : But a small number, perhaps less than 5% have them regularly.
P : In fact, only recently have there been serious studies to find out how many of us actually have nightmares.
Q : Now that is changing.
R : But the study of nightmares has been curiously neglected.
S : While results so far are inconclusive, it seems fair to say that at least half the population has occasional nightmares.
The proper sequence should be

Options

A. S R P Q
B. R Q P S
C. P Q R S
D. S Q R P