[A] : Viruses are obligate parasites .
[R] : Viruses can not multiply outside the host .

Options

A. 1)If both A and R are true and R is the correct explanation of A
B. 2)If both A and R are true but R is not the correct explanation of A
C. 3)If A is true and R is false
D. 4)If both A and R are false