Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).Assertion (A): Osteoporosis is characterised by decreased bone mass and increased chances of fracture.Reason (R): Common cause of osteoporosis is increased levels of oestrogen.In the light of the above statements, choose the most appropriate answer from the options given:

1. A
   Both (A) and (R) are correct and (R) is the correct explanation of (A)
2. B
   Both (A) and (R) are correct but (R) is not the correct explanation of (A)
3. C
   (A) is correct but (R) is not correct
4. D
   (A) is not correct but (R) is correct