Assertion(A): Australian marsupials can be taken as an example of adaptive radiation.
Reason(R): A number of marsupials, evolved from an ancestral stock, but all within the Australian island continent.
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true but (R) is not the correct explanation of (A).
3. (A) is true but (R) is false.
4. Both (A) and (R) are false.