The correct option is
B S P R Q
The first statement in the sequence should be the one that best connects with S1. It should be a continuation or extension of S1.
S is first in the sequence: S1 starts to talk about one of the most widely spread of bad habits. S continues this topic by telling us that the habit is the use of tobacco.
S is followed by P: P tells us more about S. It says that this tobacco is now smoked or chewed by men.
P is followed by R: R adds to P. It says that it also often chewed or smoked by women.
R is followed by Q: Q adds to R. It says that sometimes it done even by children. S6 continues R's point by saying that this happens almost all over the world.
Finally, the correct sentence is 'One of the most widely spread of bad habits is the use of tobacco which is now smoked or chewed by men often by women and even by children almost all over the world'.
Thus, the correct sequence is S P R Q. Hence, A is the correct option.