Given below are two statements. One is labelled as Assertion A and other labelled as Reason R
Assertion A: Thalassemia and sickle cell anaemia in man are caused due to a problem in globin molecule synthesis.  
Reason R: Thalassemia differs from sickle cell anaemia in that thalassemia is a qualitative problem of synthesizing an incorrectly functioning globin whereas sickle cell anaemia is a quantitative problem of synthesizing a few globin molecules.

In light of the above statements, choose the correct answer from the options given below