Question on Regular expression - 2

Question

Answer given as : e 

But , my question is (P*Q*) * = {null string , any number of P , any number of Q , P followed by Q , }

whereas (P*+Q*)* = { null string , any number of P , any number of Q ,  P followed by Q , Q followed by P }

So , in the (P*Q*)* , Q followed by P is not possible . So , how they can be equal ?

Answer 1

(P*Q*)* = null + (P*Q*) + (P*Q*)(P*Q*) + (P*Q*)(P*Q*)(P*Q*) + .....
Now lets take (P*Q*)(P*Q*);
((NULL + P + PP ...)Q*)(P*(NULL + Q + QQ + QQQ ...)
// combine Q* and null from 1st bracket and P* and null from 2nd
= (Q*P*)

rearrange P*, Q* for other combination..

Answer 2

option a is right. we try to genrete p or q .