The first statement in the sequence should be the one that introduces a new topic. It should not be a continuation or extension of a topic.
Q is first in the sequence: Q is the only phrase that introduces a new topic. It starts a discussion on bear market and gives it definition.
Q is followed by S: S continues Q's point. It tells us where the term 'bear market' is used.
S is followed by R: R is an extension of S. It tells us another possible place where the term can be employed. It says that bear can also be applied to stocks sold at a future date.
R is followed by P: P explains the point introduced by R. It tells us in detail about the application of bear mentioned in R.
Thus, the correct sequence is Q S R P. Hence, A is the correct option.