Assertion(A): 20 amino acids have to be coded by the combination of four bases.
Reason(R): Each nucleic acid has four types of bases.
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. (A) is false, but (R) is true.