Assertion (A) : The Darwinian theory of natural selection sometimes referred to as 'the survival of the fittest' explains the origin of many species as a normal process of descent from parent forms.Reason (R) :The contemporary distribution pattern of many organisms is often the result of natural migration or dispersal from original center(s) of development.Code

• A. Both (A) and (R) are true and (R) is the correct explanation of (A)
• B. Both (A) and (R) are true but (R) is not the correct explanation of (A)
• C. (A) is true but (R) is false
• D. (A) is false but (R) is true