**Answer:**** A**

Let the marks scored by P,Q,R and S be a, ak, ak^{2} and ak^{3} respectively.

Marks scored by R were 275/9% less than the marks scored by P and Q.

So, if marks scored by P and Q were 36 then those scored by R is 25.

Marks scored by P and Q = a+ak =36

Marks scored by R = ak^{2} =25

=> (a+ak)/ak^{2} = 36/25 => k= 5/4.

P =a, Q = 5a/4, R= 25a/16, S = 125a/64

=> P= 64a, Q = 80 a, R = 100a and S = 125a

S scored (125a-80)/80a * 100 more than Q

=> (45/80) * 100 = 56.25%

S scored 56.25% more than Q..